code: def get_algo_df(algo_name, key, environ=None, rel_path=None):
      """
      The de-serialized DataFrame of an algo name and key.
  
      Parameters
      ----------
      algo_name: str
      key: str
      environ:
      rel_path: str
  
      Returns
      -------
      DataFrame
  
      """
      folder = get_algo_folder(algo_name, environ)
  
      if rel_path is not None:
          folder = os.path.join(folder, rel_path)
  
      filename = os.path.join(folder, key + ".csv")
  
      if os.path.isfile(filename):
          try:
              with open(filename, "rb") as handle:
                  return pd.read_csv(
                      handle, index_col=0, parse_dates=True
                  )
          except IOError:
              return pd.DataFrame()
      else:
          return pd.DataFrame()
  
imports: import hashlib
  import json
  import os
  import pickle
  import shutil
  from datetime import date, datetime
  import pandas
  from catalyst.assets._assets import TradingPair
  from six import string_types
  from six.moves.urllib import request
  from catalyst.constants import DATE_FORMAT, SYMBOLS_URL
  from catalyst.exchange.exchange_errors import ExchangeSymbolsNotFound
  from catalyst.exchange.utils.serialization_utils import ExchangeJSONEncoder, ExchangeJSONDecoder
  from catalyst.utils.memoize import weak_lru_cache
  from catalyst.utils.paths import data_root, ensure_directory, last_modified_time
label_desc: Use image node_id 16 for calling a global function with example usage: get_algo_df(algo_name, key, environ, rel_path) and returns: pd, pd, pd