1 files changed, 6 insertions, 3 deletions

diff --git a/python/gats.py b/python/gats.py
index 22463ab..adf5122 100644
--- a/python/gats.py
+++ b/python/gats.py
@@ -85,6 +85,9 @@ def dump( obj, sOut ):
         sOut.write(     struct.pack('>BI', 1, len(sCore)+5 ) )
         sOut.write( sCore )
 
+class EndMarker:
+        pass
+
 def _readObj( sIn ):
         t = sIn.read( 1 )
         if t == 'i':    # Integer
@@ -100,14 +103,14 @@ def _readObj( sIn ):
                 ret = []
                 while True:
                         value = _readObj( sIn )
-                        if value is None:
+                        if isinstance( value, EndMarker ):
                                 return ret
                         ret.append( value )
         elif t == 'd':  # Dictionary
                 ret = {}
                 while True:
                         key = _readObj( sIn )
-                        if key is None:
+                        if isinstance( key, EndMarker ):
                                 return ret
                         if not isinstance( key, str ):
                                 raise Exception('Only strings can be used as keys in gats dictionaries')
@@ -149,7 +152,7 @@ def _readObj( sIn ):
         elif t == 'n':
                 return None
         elif t == 'e':  # End marker
-                return None
+                return EndMarker()
         else:
                 raise Exception('Invalid gats type discovered: ' + t)
         return 'not implemented yet';