diff --git a/pySim/filesystem.py b/pySim/filesystem.py
index e97fbf6..097661d 100644
--- a/pySim/filesystem.py
+++ b/pySim/filesystem.py
@@ -65,7 +65,7 @@
         self.parent = parent
         if self.parent and self.parent != self and self.fid:
             self.parent.add_file(self)
-        self.shell_commands: List[CommandSet] = []
+        self.shell_commands = [] # type: List[CommandSet]
 
 	# Note: the basic properties (fid, name, ect.) are verified when
 	# the file is attached to a parent file. See method add_file() in