TypeError basestring type cannot be instantiated #65

After upgrading fitparse to the latest (master branch), one of my standard test files fails to parse. This is a file produced by a NK SpeedCoach GPS 2 device. The file parses well on SportTracks, Strava, etc.

C:\Users\e408191\AppData\Local\Continuum\Anaconda2\lib\site-packages\fitparse\base.pyc in _parse_raw_values_from_data_message(self, def_mesg)
244 is_byte = base_type.name == 'byte'
245 # Struct to read n base types (field def size / base type size)
--> 246 struct_fmt = str(int(field_def.size / base_type.size)) + base_type.fmt
247
248 # Extract the raw value, ask for a tuple if it's a byte type

TypeError: The basestring type cannot be instantiated

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