docstr: Returns the catalyst.utils.calendar.trading_calendar used to read
  the data.  Can be None (if the writer didn't specify it).
docstr_tok: ["Returns","the","catalyst.utils.calendar.trading_calendar","used","to","read","the","data",".","Can","be","None","(","if","the","writer","did","n't","specify","it",")","."]
code: def trading_calendar(self):
      """
      Returns the catalyst.utils.calendar.trading_calendar used to read
      the data.  Can be None (if the writer didn't specify it).
      """
      pass
  
file_path: catalyst/catalyst/data/bar_reader.py
imports: from abc import ABCMeta, abstractmethod, abstractproperty
  from six import with_metaclass
label_desc: Use image node_id 4 for calling the BarReader obj's underlying member method code with example usage: obj.trading_calendar() without return types