Import and PEP8 cleanups

apps/documents/models.py

@@ -547,7 +547,7 @@ class DocumentVersion(models.Model):
     def rename(self, new_name):
         new_filename, new_extension = os.path.splitext(new_name)
         name, extension = os.path.splitext(self.filename)
-        
+
         # Preserve existing extension if new name doesn't has one
         if new_extension:
             extension = new_extension