code: def fetch_mmtf(pdb_code: str) -> pd.DataFrame:
      """Returns a dataframe from a PDB code.
  
      :param pdb_code: 4-letter PDB accession code
      :type pdb_code: str
      :return: Dataframe of protein structure
      :rtype: pd.DataFrame
      """
      df = fetch(pdb_code)
      return mmtf_to_df(df)
  
imports: from __future__ import annotations
  import os
  import copy
  import gzip
  import warnings
  from string import ascii_uppercase
  from typing import Any, Dict, List, Union
  from warnings import warn
  import numpy
  import pandas
  from looseversion import LooseVersion
  from mmtf import MMTFDecoder, MMTFEncoder, fetch, parse, parse_gzip
  from biopandas.constants import protein_letters_3to1_extended
  from ..pdb.engines import amino3to1dict, pdb_df_columns, pdb_records
label_desc: Use image node_id 1 for calling a global function with example usage: fetch_mmtf(pdb_code) and returns: mmtf_to_df