docs: def definitiondir(self, filetype, **kwargs):
          """Returns definition subdirectory in :envvar:`PLATELIST_DIR` of the form: ``NNNNXX``.
  
          Parameters
          ----------
          filetype : str
              File type parameter.
          designid : int or str
              Design ID number.  Will be converted to int internally.
  
          Returns
          -------
          definitiondir : str
              Definition directory in the format ``NNNNXX``.
          """
  
          designid = int(kwargs['designid'])
          designid100 = designid // 100
          subdir = "{:0>4d}".format(designid100) + "XX"
          return subdir