[data] Fix print statements

beat/backend/python/data.py

@@ -823,9 +823,9 @@ class StdoutDataSink(DataSink):
         """
 
         if self.display_data:
-            print '%s(%d -> %d): %s' % (self.prefix, start_data_index, end_data_index, str(data))
+            print('%s(%d -> %d): %s' % (self.prefix, start_data_index, end_data_index, str(data)))
         else:
-            print '%s(%d -> %d): <data>' % (self.prefix, start_data_index, end_data_index)
+            print('%s(%d -> %d): <data>' % (self.prefix, start_data_index, end_data_index))
 
 
     def isConnected(self):