diff --git a/esprima/character.py b/esprima/character.py
index 929706c..2b225fd 100644
--- a/esprima/character.py
+++ b/esprima/character.py
@@ -82,7 +82,7 @@
 
 del U_CATEGORIES, UNICODE_LETTER, UNICODE_COMBINING_MARK
 del UNICODE_DIGIT, UNICODE_CONNECTOR_PUNCTUATION
-del DECIMAL_CONV, OCTAL_CONV, HEX_CONV
+# del DECIMAL_CONV, OCTAL_CONV, HEX_CONV
 
 class Character:
     @staticmethod
diff --git a/esprima/visitor.py b/esprima/visitor.py
index ad32375..236f0c4 100644
--- a/esprima/visitor.py
+++ b/esprima/visitor.py
@@ -282,7 +282,12 @@ def visit_dict(self, obj):
                 v = yield item
                 k = unicode(k)
                 items.append((self.map.get(k, k), v))
-        yield Visited(dict(items))
+        items = dict(items)
+        if "type" in items.keys() and "raw" in items.keys() and items["type"] == 'Literal' and items["raw"] == "null":
+            items["value"] = None
+        if "type" in items.keys() and "raw" in items.keys() and items["type"] == 'Literal' and "regex" in items.keys() and type(items["value"]) == re.Pattern:
+            items["value"] = None
+        yield Visited(items)
 
     def visit_SRE_Pattern(self, obj):
         yield Visited({})