code: def _get_variable_from_filepath(self):
          
          try:
              return self.regexp_capture_variable.search(self.filepath).group(1)
          except AttributeError:
              self._raise_cannot_determine_variable_from_filepath_error()
docs: Determine the file variable from the filepath.
  
          Returns
          -------
          str
              Best guess of variable name from the filepath