diff --git a/ebuildtester/docker.py b/ebuildtester/docker.py
index 6e4985c..a2e6acb 100644
--- a/ebuildtester/docker.py
+++ b/ebuildtester/docker.py
@@ -203,8 +203,8 @@ def _tweak_settings(self):
 
         # Disable the usersandbox feature, it's not working well inside a
         # docker container.
-        self.execute("echo FEATURES=\\\"{}\\\" "
-                     ">> /etc/portage/make.conf".format(features))
+        self.execute(f"echo FEATURES=\\\"{features}\\\" "
+                     ">> /etc/portage/make.conf")
 
         self.execute(("echo MAKEOPTS=\\\"-j%d\\\" " %
                       (options.options.threads)) +
diff --git a/ebuildtester/parse.py b/ebuildtester/parse.py
index 7378a25..4d42c20 100644
--- a/ebuildtester/parse.py
+++ b/ebuildtester/parse.py
@@ -19,6 +19,11 @@ def parse_commandline(args):
         help="The package atom(s) to install",
         nargs="+",
         action="append")
+    parser.add_argument(
+        "--refresh-manifest",
+        help="Refresh the package manifest before installing",
+        action="store_true"
+    )
     parser.add_argument(
         "--binhost",
         help="Binhost URI")