code: def write_nodes(gtfs, output, fields=None):
      
      nodes = gtfs.get_table("stops")
      if fields is not None:
          nodes = nodes[fields]
      with util.create_file(output, tmpdir=True, keepext=True) as tmpfile:
          nodes.to_csv(tmpfile, encoding='utf-8', index=False, sep=";")
docs: Parameters
      ----------
      gtfs: gtfspy.GTFS
      output: str
          Path to the output file
      fields: list, optional
          which pieces of information to provide