diff --git a/main.py b/main.py
index abb99cc5..3efb1c35 100755
--- a/main.py
+++ b/main.py
@@ -69,7 +69,7 @@ from wrapper import WrapperPath, Wrapper
 from subcmds import all_commands
 
 if not is_python3():
-  input = raw_input
+  input = raw_input  # noqa: F821
 
 global_options = optparse.OptionParser(
     usage='repo [-p|--paginate|--no-pager] COMMAND [ARGS]',
diff --git a/platform_utils_win32.py b/platform_utils_win32.py
index c59db523..a6286374 100644
--- a/platform_utils_win32.py
+++ b/platform_utils_win32.py
@@ -219,8 +219,8 @@ def _preserve_encoding(source, target):
   if is_python3():
     return target
 
-  if isinstance(source, unicode):
-    return unicode(target)
+  if isinstance(source, unicode):  # noqa: F821
+    return unicode(target)  # noqa: F821
   return str(target)
 
 
diff --git a/project.py b/project.py
index 4af062ac..d0bf4651 100644
--- a/project.py
+++ b/project.py
@@ -52,7 +52,7 @@ else:
   import urlparse
   urllib = imp.new_module('urllib')
   urllib.parse = urlparse
-  input = raw_input
+  input = raw_input  # noqa: F821
 
 
 def _lwrite(path, content):
diff --git a/subcmds/gitc_delete.py b/subcmds/gitc_delete.py
index 1011276f..24d355a2 100644
--- a/subcmds/gitc_delete.py
+++ b/subcmds/gitc_delete.py
@@ -22,7 +22,7 @@ import platform_utils
 
 from pyversion import is_python3
 if not is_python3():
-  input = raw_input
+  input = raw_input  # noqa: F821
 
 
 class GitcDelete(Command, GitcClientCommand):
diff --git a/subcmds/upload.py b/subcmds/upload.py
index bc373b3e..ba75a53e 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -27,7 +27,7 @@ from project import RepoHook
 
 from pyversion import is_python3
 if not is_python3():
-  input = raw_input
+  input = raw_input  # noqa: F821
 else:
   unicode = str