Moving contains

nptdms/tdms.py

@@ -137,13 +137,6 @@ def __init__(self, file, raw_timestamps=False, memmap_dir=None, read_metadata_on
             if not keep_open:
                 self._reader.close()
 
-    def __contains__(self, group_name):
-        """ Check if TDMS file contains groupp
-
-        :rtype: Boolean
-        """
-        return group_name in self._groups
-
     def groups(self):
         """Returns a list of the groups in this file
 
@@ -221,6 +214,13 @@ def __len__(self):
         """
         return len(self._groups)
 
+    def __contains__(self, group_name):
+        """ Check if TDMS file contains groupp
+
+        :rtype: Boolean
+        """
+        return group_name in self._groups
+
     def __iter__(self):
         """ Returns an iterator over the names of groups in this file
         """