diff --git a/lib/tfw/components/source_code_event_handler.py b/lib/tfw/components/source_code_event_handler.py
index 8e795da..9b0fcf6 100644
--- a/lib/tfw/components/source_code_event_handler.py
+++ b/lib/tfw/components/source_code_event_handler.py
@@ -43,7 +43,7 @@ class FileManager:
     @filename.setter
     def filename(self, filename):
         if not filename in self.files:
-           raise EnvironmentError('No such file in workdir!')
+            raise EnvironmentError('No such file in workdir!')
         self._filename = filename
 
     @property