code: def _extract(self, source, *args, **kwargs):
          
          # Extract git test_data
          self._data = extract_log(source)
  
          # Shorten hashes
          self._data['hexsha'] = self._data['hexsha'].apply(lambda s: s[:7])
docs: Extracts data from a local git repository. Mutates _data.
          :param str source: The path to a local git repository.
          :param args: Arbitrary arguments for extensibility.
          :param kwargs: Arbitrary keyword arguments for extensibility.
  
          :return: None