diff --git a/build-android.xml b/build-android.xml
index 027f2dad6c..e3f4c452fb 100644
--- a/build-android.xml
+++ b/build-android.xml
@@ -17,6 +17,14 @@
   <fail message="sdk.dir is missing. Make sure to generate local.properties using 'android update project' or to inject it through the ANDROID_HOME environment variable."
         unless="sdk.dir" />
 
+  <fail message="android.jar not found at ${sdk.dir}/platforms/${target.platform}/, is your ANDROID_TARGET set?">
+    <condition>
+        <not>
+          <available file="${sdk.dir}/platforms/${target.platform}/android.jar"/>
+        </not>
+    </condition>
+  </fail>
+
   <target name="compile" description="Compile the Android-specific source">
     <mkdir dir="${build}/android"/>
     <javac debug="true"
diff --git a/python/common/org/Python.java b/python/common/org/Python.java
index ece77d2f3e..ac92e7708a 100644
--- a/python/common/org/Python.java
+++ b/python/common/org/Python.java
@@ -786,7 +786,7 @@ public static org.python.Object filter(org.python.Object function, org.python.Ob
     )
     public static org.python.types.Str format(org.python.Object value, org.python.Object format_spec) {
         if (format_spec == null) {
-            return (org.python.types.Str) value.__str__();
+			return (org.python.types.Str) value.__format__(new org.python.types.Str(""));
         } else {
             return (org.python.types.Str) value.__format__(format_spec);
         }
diff --git a/python/common/org/python/Object.java b/python/common/org/python/Object.java
index 9c840d5bf7..20089ca381 100644
--- a/python/common/org/python/Object.java
+++ b/python/common/org/python/Object.java
@@ -48,7 +48,7 @@ public interface Object extends Comparable {
     public org.python.Object __str__();
 
     public org.python.Object __bytes__();
-    public org.python.Object __format__(org.python.Object format);
+    public org.python.Object __format__(org.python.Object format_spec);
 
     public org.python.Object __lt__(org.python.Object other);
     public org.python.Object __le__(org.python.Object other);
diff --git a/python/common/org/python/types/Bool.java b/python/common/org/python/types/Bool.java
index fb31ec0287..876a2d295c 100644
--- a/python/common/org/python/types/Bool.java
+++ b/python/common/org/python/types/Bool.java
@@ -68,13 +68,6 @@ public org.python.types.Str __repr__() {
         }
     }
 
-    @org.python.Method(
-            __doc__ = ""
-    )
-    public org.python.types.Str __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("'bool'.__format__ has not been implemented.");
-    }
-
     @org.python.Method(
             __doc__ = "",
             args = {"index", "value"}
diff --git a/python/common/org/python/types/ByteArray.java b/python/common/org/python/types/ByteArray.java
index b7c2baaef2..c1dca65c49 100644
--- a/python/common/org/python/types/ByteArray.java
+++ b/python/common/org/python/types/ByteArray.java
@@ -592,12 +592,6 @@ public org.python.Object __contains__(org.python.Object slice) {
         return new Bytes(this.value).__contains__(slice);
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(java.util.List<org.python.Object> args, java.util.Map<java.lang.String, org.python.Object> kwargs, java.util.List<org.python.Object> default_args, java.util.Map<java.lang.String, org.python.Object> default_kwargs) {
-        throw new org.python.exceptions.NotImplementedError("bytearray.__format__ has not been implemented.");
-    }
 
     @org.python.Method(
             __doc__ = ""
diff --git a/python/common/org/python/types/Bytes.java b/python/common/org/python/types/Bytes.java
index e2e3722067..3ef5644b33 100644
--- a/python/common/org/python/types/Bytes.java
+++ b/python/common/org/python/types/Bytes.java
@@ -251,12 +251,6 @@ public org.python.Object __contains__(org.python.Object slice) {
         return org.python.types.Bool.FALSE;
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(java.util.List<org.python.Object> args, java.util.Map<java.lang.String, org.python.Object> kwargs, java.util.List<org.python.Object> default_args, java.util.Map<java.lang.String, org.python.Object> default_kwargs) {
-        throw new org.python.exceptions.NotImplementedError("bytes.__format__ has not been implemented.");
-    }
 
     @org.python.Method(
             __doc__ = "Return self>=value.",
diff --git a/python/common/org/python/types/Complex.java b/python/common/org/python/types/Complex.java
index afda805bad..2680de77a9 100644
--- a/python/common/org/python/types/Complex.java
+++ b/python/common/org/python/types/Complex.java
@@ -161,39 +161,49 @@ private String partToStr(org.python.types.Float x) {
             __doc__ = "Return repr(self)."
     )
     public org.python.Object __repr__() {
-        java.lang.StringBuilder buffer = new java.lang.StringBuilder();
-        boolean real_present = true;
-        if (this.real.value != 0) {
-            buffer.append("(");
-            if (((org.python.types.Bool) ((this.real).__int__().__eq__(this.real))).value) {
-                buffer.append(((org.python.types.Str) this.real.__int__().__repr__()).value);
-            } else {
-                buffer.append(((org.python.types.Str) this.real.__repr__()).value);
-            }
+
+        if (this.real.value != 0.0 || this.real.isNegativeZero()) {
+            return new org.python.types.Str("(" + partToStr(this.real) + ((this.imag.value >= 0.0 && !this.imag.isNegativeZero()) ? "+" : "-") + partToStr(new org.python.types.Float(Math.abs(this.imag.value))) + "j)");
         } else {
-            real_present = false;
+            return new org.python.types.Str(partToStr(this.imag) + "j");
         }
-        if (this.real.value != 0 && this.imag.value >= 0) {
+
+    }
+
+
+    @org.python.Method(
+					   __doc__ = "complex.__format__() -> str\n\nConvert to a string according to format_spec.",
+					   args={"format_spec"}
+    )
+    public org.python.Object __format__(org.python.Object format_spec) {
+		String fs = ((org.python.types.Str) format_spec).value;
+
+
+		if(!(fs.endsWith("f")
+			 ||fs.endsWith("F")
+			 ||fs.endsWith("g")
+			 ||fs.endsWith("G")
+			 ||fs.endsWith("e")
+			 ||fs.endsWith("E")
+         	 ||fs.endsWith("n")
+			 )){
+			//format specs are ignored by python for complex numbers if no floatingpoit spec is present
+			return this.__repr__();
+		}
+		// use the floating point spec
+
+        java.lang.StringBuilder buffer = new java.lang.StringBuilder();
+
+		buffer.append(((org.python.types.Str) this.real.__format__(format_spec)).value);
+
+        if (this.imag.value >= 0) {
             buffer.append("+");
         }
-        if (((org.python.types.Bool) ((this.imag).__int__().__eq__(this.imag))).value) {
-            buffer.append(((org.python.types.Str) (this.imag).__int__().__repr__()).value);
-        } else {
-            buffer.append(((org.python.types.Str) (this.imag).__repr__()).value);
-        }
+		buffer.append(((org.python.types.Str) (this.imag).__format__(format_spec)).value);
         buffer.append("j");
-        if (real_present) {
-            buffer.append(")");
-        }
         return new org.python.types.Str(buffer.toString());
-    }
 
-    @org.python.Method(
-            __doc__ = "complex.__format__() -> str\n\nConvert to a string according to format_spec."
-    )
-    public org.python.Object __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("complex.__format__ has not been implemented.");
-    }
+	}
 
     @org.python.Method(
             __doc__ = "Return self<value.",
@@ -302,16 +312,6 @@ public org.python.Object __sub__(org.python.Object other) {
         throw new org.python.exceptions.TypeError("unsupported operand type(s) for -: 'complex' and '" + other.typeName() + "'");
     }
 
-    @org.python.Method(
-            __doc__ = "Return str(self)."
-    )
-    public org.python.Object __str__() {
-        if (this.real.value != 0.0 || this.real.isNegativeZero()) {
-            return new org.python.types.Str("(" + partToStr(this.real) + ((this.imag.value >= 0.0 && !this.imag.isNegativeZero()) ? "+" : "-") + partToStr(new org.python.types.Float(Math.abs(this.imag.value))) + "j)");
-        } else {
-            return new org.python.types.Str(partToStr(this.imag) + "j");
-        }
-    }
 
     @org.python.Method(
             __doc__ = "Return self*value.",
diff --git a/python/common/org/python/types/Dict.java b/python/common/org/python/types/Dict.java
index d82ba1d244..0b2037bd73 100644
--- a/python/common/org/python/types/Dict.java
+++ b/python/common/org/python/types/Dict.java
@@ -135,13 +135,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(org.python.Object other) {
-        throw new org.python.exceptions.NotImplementedError("dict.__format__() has not been implemented.");
-    }
-
     @org.python.Method(
             __doc__ = ""
     )
diff --git a/python/common/org/python/types/DictKeys.java b/python/common/org/python/types/DictKeys.java
index 08c16200b3..8c41c3e491 100644
--- a/python/common/org/python/types/DictKeys.java
+++ b/python/common/org/python/types/DictKeys.java
@@ -56,12 +56,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(org.python.Object other) {
-        throw new org.python.exceptions.NotImplementedError(this.typeName() + ".__format__() has not been implemented.");
-    }
 
     @org.python.Method(
             __doc__ = "__dir__() -> list\ndefault dir() implementation"
diff --git a/python/common/org/python/types/DictValues.java b/python/common/org/python/types/DictValues.java
index 86c4da18a9..05cfa681d2 100644
--- a/python/common/org/python/types/DictValues.java
+++ b/python/common/org/python/types/DictValues.java
@@ -47,13 +47,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(org.python.Object other) {
-        throw new org.python.exceptions.NotImplementedError(this.typeName() + ".__format__() has not been implemented.");
-    }
-
     @org.python.Method(
             __doc__ = "__dir__() -> list\ndefault dir() implementation"
     )
diff --git a/python/common/org/python/types/Float.java b/python/common/org/python/types/Float.java
index 9f7ee8b3a7..fe2c9cd556 100644
--- a/python/common/org/python/types/Float.java
+++ b/python/common/org/python/types/Float.java
@@ -59,6 +59,41 @@ public Float(org.python.Object[] args, java.util.Map<java.lang.String, org.pytho
             __doc__ = "Return repr(self)."
     )
     public org.python.types.Str __repr__() {
+		String format = ".17g";
+        return this.__format__(new org.python.types.Str(format));
+    }
+
+    @org.python.Method(
+            __doc__ = ""
+    )
+    public boolean isNegativeZero() {
+        return Double.doubleToRawLongBits(this.value) == NEGATIVE_ZERO_RAW_BITS;
+    }
+
+    @org.python.Method(
+					   __doc__ = "float.__format__(format_spec) -> string\n\nFormats the float according to format_spec.",
+					   args = {"format_spec"}
+    )
+    public org.python.types.Str __format__(org.python.Object format_spec) {
+		String format = ((org.python.types.Str) format_spec).value;
+		if(format.endsWith("%")){
+			org.python.types.Str new_format = new org.python.types.Str(format.substring(0,-1)+"f");
+			org.python.types.Float new_float = new org.python.types.Float(this.value*100);
+			return new_float.__format__(new_format);
+		}
+		if(format.endsWith("n")){
+			throw new org.python.exceptions.NotImplementedError("float formatting with 'n' formatter has not been implemented.");
+		}
+		if(format.length() == 0 || !Character.isLetter(format.charAt(format.length()-1))){
+			// use g as default formatter
+			if(format.indexOf('.') <0){
+				//  if no precision is given use .17
+				format += ".17g";
+			}else{
+				format += "g";
+			}
+		}
+		// handle e, E, f, F, g, G or None formatters
         double value = this.value;
         String result;
         if (Double.isNaN(value)) {
@@ -70,56 +105,50 @@ public org.python.types.Str __repr__() {
                 result = "-inf";
             }
         } else {
-            String format = "%.17g";
-            result = String.format(Locale.US, format, value);
-            int dot_pos = result.indexOf(".");
-            int e_pos = result.indexOf("e");
-            if (dot_pos != -1) {
-                // Remove trailing zeroes in the fractional part
-                int last_zero = -1;
-                int i;
-                for (i = dot_pos + 1; i < result.length(); i++) {
-                    char c = result.charAt(i);
-                    if (i == e_pos) {
-                        break;
-                    } else if (c == '0') {
-                        if (last_zero == -1) {
-                            last_zero = i;
-                        }
-                    } else {
-                        last_zero = -1;
-                    }
-                }
-                if (last_zero != -1) {
-                    if (last_zero == dot_pos + 1) {
-                        // Everything after the dot is zeros
-                        if (e_pos == -1) {
-                            // If there's no "e", leave ".0" at the end
-                            last_zero += 1;
-                        } else {
-                            // If there is an "e", nuke the dot as well
-                            last_zero -= 1;
-                        }
-                    }
-                    result = result.substring(0, last_zero) + result.substring(i);
-                }
-            }
+			result = String.format(Locale.US, "%"+format, value);
+			if(format.endsWith("g")
+				  || format.endsWith("G")){
+
+				// Check whether we need to remove trailing zeros when not using g or G as a formatter
+				int dot_pos = result.indexOf(".");
+				int e_pos = result.indexOf("e");
+				if (dot_pos != -1) {
+					// Remove trailing zeroes in the fractional part
+					int last_zero = -1;
+					int i;
+					for (i = dot_pos + 1; i < result.length(); i++) {
+						char c = result.charAt(i);
+						if (i == e_pos) {
+							break;
+						} else if (c == '0') {
+							if (last_zero == -1) {
+								last_zero = i;
+							}
+						} else {
+							last_zero = -1;
+						}
+					}
+					if (last_zero != -1) {
+						if (last_zero == dot_pos + 1) {
+							// Everything after the dot is zeros
+							if (e_pos == -1) {
+								// If there's no "e", leave ".0" at the end
+								last_zero += 1;
+							} else {
+								// If there is an "e", nuke the dot as well
+								last_zero -= 1;
+							}
+						}
+						result = result.substring(0, last_zero) + result.substring(i);
+					}
+				}
+			}
         }
+		if(format.endsWith("G")|| format.endsWith("F") || format.endsWith("E")){
+			result = result.toUpperCase();
+		}
         return new org.python.types.Str(result);
-    }
 
-    @org.python.Method(
-            __doc__ = ""
-    )
-    public boolean isNegativeZero() {
-        return Double.doubleToRawLongBits(this.value) == NEGATIVE_ZERO_RAW_BITS;
-    }
-
-    @org.python.Method(
-            __doc__ = "float.__format__(format_spec) -> string\n\nFormats the float according to format_spec."
-    )
-    public org.python.types.Str __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("float.__format__() has not been implemented.");
     }
 
     @org.python.Method(
diff --git a/python/common/org/python/types/Int.java b/python/common/org/python/types/Int.java
index 3c36ebeff2..44ca2336e2 100644
--- a/python/common/org/python/types/Int.java
+++ b/python/common/org/python/types/Int.java
@@ -1,5 +1,7 @@
 package org.python.types;
 
+import java.util.Locale;
+
 public class Int extends org.python.types.Object {
     public long value;
 
@@ -128,10 +130,24 @@ public org.python.types.Str __repr__() {
     }
 
     @org.python.Method(
-            __doc__ = ""
+					   __doc__ = "",
+					   args = {"format_spec"}
     )
-    public org.python.types.Str __format__(org.python.Object format_str) {
-        throw new org.python.exceptions.NotImplementedError("int.__format__() has not been implemented");
+    public org.python.types.Str __format__(org.python.Object format_spec) {
+
+		String fs = ((org.python.types.Str) format_spec).value;
+		if(fs.endsWith("n"))
+			throw new org.python.exceptions.NotImplementedError("int formatting with 'n' as formatter has not been implemented");
+		if(fs.endsWith("b"))
+			throw new org.python.exceptions.NotImplementedError("int formatting with 'b' as formatter has not been implemented");
+
+		if(fs.length() == 0 || !Character.isLetter(fs.charAt(fs.length()-1))){
+			// use d as default formatter
+			fs += "d";
+		}
+
+
+		return new org.python.types.Str(String.format(Locale.US,"%"+fs,this.value));
     }
 
     @org.python.Method(
diff --git a/python/common/org/python/types/List.java b/python/common/org/python/types/List.java
index 2bea847afb..29f2c13dcf 100644
--- a/python/common/org/python/types/List.java
+++ b/python/common/org/python/types/List.java
@@ -153,13 +153,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__() {
-        throw new org.python.exceptions.NotImplementedError("list.__format__() has not been implemented.");
-    }
-
     @org.python.Method(
             __doc__ = "Return self<value.",
             args = {"other"}
diff --git a/python/common/org/python/types/Object.java b/python/common/org/python/types/Object.java
index 820817de7d..32da079f81 100644
--- a/python/common/org/python/types/Object.java
+++ b/python/common/org/python/types/Object.java
@@ -172,11 +172,15 @@ public org.python.Object __bytes__() {
 
     @org.python.Method(
             __doc__ = "default object formatter",
-            args = {"format_string"}
-    )
-    public org.python.Object __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("'" + this.typeName() + ".__format__' has not been implemented");
-    }
+            args = {"format_spec"}
+    )
+    public org.python.Object __format__(org.python.Object format_spec) {
+		if( format_spec != null &&
+			((org.python.types.Str) format_spec).value != ""){
+			throw new org.python.exceptions.TypeError("on-empty format string passed to object.__format__");
+		}
+		return this.__str__();
+	}
 
     @org.python.Method(
             __doc__ = "Return self<value.",
diff --git a/python/common/org/python/types/Set.java b/python/common/org/python/types/Set.java
index 9b48e27c6e..786982cf6a 100644
--- a/python/common/org/python/types/Set.java
+++ b/python/common/org/python/types/Set.java
@@ -102,12 +102,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("__format__() has not been implemented");
-    }
 
     @org.python.Method(
             __doc__ = "",
diff --git a/python/common/org/python/types/Str.java b/python/common/org/python/types/Str.java
index ac7f214f74..280ff0f01e 100644
--- a/python/common/org/python/types/Str.java
+++ b/python/common/org/python/types/Str.java
@@ -139,10 +139,14 @@ public org.python.Object __str__() {
     }
 
     @org.python.Method(
-            __doc__ = "S.__format__(format_spec) -> str\n\nReturn a formatted version of S as described by format_spec."
-    )
-    public org.python.Object __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("__format__() has not been implemented.");
+					   __doc__ = "S.__format__(format_spec) -> str\n\nReturn a formatted version of S as described by format_spec.",
+					   args = {"format_spec"}
+    )
+    public org.python.Object __format__(org.python.Object format_spec) {
+		String fs = ((org.python.types.Str) format_spec).value;
+		if(!fs.endsWith("s"))
+			fs += "s";
+		return new org.python.types.Str(String.format("%"+fs,this.value));
     }
 
     @org.python.Method(
diff --git a/python/common/org/python/types/Super.java b/python/common/org/python/types/Super.java
index fc2bdbc38a..58e93a10e4 100644
--- a/python/common/org/python/types/Super.java
+++ b/python/common/org/python/types/Super.java
@@ -120,12 +120,12 @@ public org.python.Object __bytes__() {
         throw new org.python.exceptions.AttributeError(this, "__bytes__");
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter",
-            args = {"format_string"}
+	@org.python.Method(
+					   __doc__ = "",
+					   args = {"format_spec"}
     )
-    public org.python.Object __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("'super().__format__' has not been implemented");
+    public org.python.Object __format__(org.python.Object format_spec) {
+		return this.__str__();
     }
 
     @org.python.Method(
diff --git a/python/common/org/python/types/Tuple.java b/python/common/org/python/types/Tuple.java
index c35bf0e9b9..5822364df9 100644
--- a/python/common/org/python/types/Tuple.java
+++ b/python/common/org/python/types/Tuple.java
@@ -84,12 +84,6 @@ public org.python.types.Str __repr__() {
         return new org.python.types.Str(buffer.toString());
     }
 
-    @org.python.Method(
-            __doc__ = "default object formatter"
-    )
-    public org.python.types.Str __format__(org.python.Object format_string) {
-        throw new org.python.exceptions.NotImplementedError("__format__() has not been implemented.");
-    }
 
     @org.python.Method(
             __doc__ = ""
diff --git a/tests/builtins/test_repr.py b/tests/builtins/test_repr.py
index 9670d923bf..05bd924d01 100644
--- a/tests/builtins/test_repr.py
+++ b/tests/builtins/test_repr.py
@@ -10,5 +10,4 @@ class BuiltinReprFunctionTests(BuiltinFunctionTestCase, TranspileTestCase):
 
     not_implemented = [
         'test_class',
-        'test_complex',
     ]
diff --git a/tests/builtins/test_slice.py b/tests/builtins/test_slice.py
index cdee0295b0..dab153c4ca 100644
--- a/tests/builtins/test_slice.py
+++ b/tests/builtins/test_slice.py
@@ -26,5 +26,4 @@ class BuiltinSliceFunctionTests(BuiltinFunctionTestCase, TranspileTestCase):
 
     not_implemented = [
         'test_class',
-        'test_complex',
     ]
diff --git a/tests/datatypes/test_dict.py b/tests/datatypes/test_dict.py
index e4cb60318a..7213d3673f 100644
--- a/tests/datatypes/test_dict.py
+++ b/tests/datatypes/test_dict.py
@@ -490,7 +490,6 @@ class BinaryDictOperationTests(BinaryOperationTestCase, TranspileTestCase):
     not_implemented = [
         'test_subscr_bytearray',
         'test_subscr_class',
-        'test_subscr_complex',
     ]
 
 
diff --git a/voc/python/ast.py b/voc/python/ast.py
index a4c9f22a8a..fd5a87e27d 100644
--- a/voc/python/ast.py
+++ b/voc/python/ast.py
@@ -1,7 +1,7 @@
 import ast
+import _ast
 import copy
 import sys
-import traceback
 
 from ..java import opcodes as JavaOpcodes
 from .modules import Module
@@ -188,6 +188,14 @@ def convert_to_Name(_node):
                         return
                     index += 1
 
+    def generic_visit(self, node):
+        # Catches node types that are not implemented
+        # Expr calls this function directly and is meant to do so
+        # Other node types mean that we are skipping something that we should not
+        if type(node) != _ast.Expr:
+            raise TypeError("Not translating node of type "+str(type(node)))
+        super().generic_visit(node)
+
     def visit(self, node):
         try:
             self.parse_yield(node)
@@ -1796,7 +1804,7 @@ def visit_Yield(self, node):
                         'Lorg/python/Object;'
                     )
                 )
-                
+
         yield_point = len(self.context.yield_points) + 1
 
         # Save the current stack and yield index
@@ -2470,6 +2478,84 @@ def visit_ExtSlice(self, node):
         # slice* dims):
         raise NotImplementedError('No handler for ExtSlice')
 
+    @node_visitor
+    def visit_JoinedStr(self, node):
+        # Joined strs are new in python 3.6+ and are used in fstrings.
+        # The easyiest way to handle them seems to be to transform them to "".join(*values)
+        transformed_node = _ast.Call(
+                lineno=node.lineno,
+                col_offset=node.col_offset,
+                func=_ast.Attribute(
+                    lineno=node.lineno,
+                    col_offset=node.col_offset,
+                    value=_ast.Str(lineno=node.lineno, col_offset=node.col_offset, s=''),
+                    attr='join',
+                    ctx=_ast.Load(),
+                ),
+                args=[
+                    _ast.List(
+                        lineno=node.lineno,
+                        col_offset=node.col_offset,
+                        elts=node.values,
+                        ctx=_ast.Load(),
+                    ),
+                ],
+                keywords=[],
+            )
+        # pass on the handling
+        self.visit(transformed_node)
+
+    @node_visitor
+    def visit_FormattedValue(self, node):
+        # Formatted values are new in pyhton 3.6+ and are used in f-strings
+        # The easyiest way to handle them seems to be to transform them to value.__format__(format_spec)
+
+        # Check if we need to call str, repr or ascii before formatting
+        if node.conversion == -1:
+            value_node = node.value
+        elif node.conversion == 114:
+            value_node = _ast.Call(
+                lineno=node.lineno,
+                col_offset=node.col_offset,
+                func=_ast.Name(lineno=node.lineno, col_offset=node.col_offset, id='repr', ctx=_ast.Load()),
+                args=[node.value],
+                keywords=[]
+                )
+        elif node.conversion == 115:
+            value_node = _ast.Call(
+                lineno=node.lineno,
+                col_offset=node.col_offset,
+                func=_ast.Name(lineno=node.lineno, col_offset=node.col_offset, id='str', ctx=_ast.Load()),
+                args=[node.value],
+                keywords=[]
+                )
+
+        elif node.conversion == 97:
+            value_node = _ast.Call(
+                lineno=node.lineno,
+                col_offset=node.col_offset,
+                func=_ast.Name(lineno=node.lineno, col_offset=node.col_offset, id='ascii', ctx=_ast.Load()),
+                args=[node.value],
+                keywords=[]
+            )
+        else:
+            raise ValueError("Conversion type %i not implemented for f-strings" % node.conversion)
+
+        formatspec = node.format_spec or _ast.Str(lineno=node.lineno, col_offset=node.col_offset, s="")
+        transformed_node = _ast.Call(lineno=node.lineno,
+                                     col_offset=node.col_offset,
+                                     func=_ast.Attribute(
+                                         lineno=node.lineno,
+                                         col_offset=node.col_offset,
+                                         value=value_node,
+                                         attr="__format__",
+                                         ctx=_ast.Load(),
+                                     ),
+                                     args=[formatspec],
+                                     keywords=[],
+                                     )
+        self.visit(transformed_node)
+
     @node_visitor
     def visit_Index(self, node):
         self.visit(node.value)