code: def set_logging(self, log_level=logging.ERROR, file_path_name=None):
          
          self.log = get_logger(log_level, file_path_name)
docs: This function allows to change the logging backend, either output or file as backend
          It also allows to set the logging level (whether to display only critical/error/info/debug.
          for example::
  
              yag = yagmail.SMTP()
              yag.set_logging(yagmail.logging.DEBUG)  # to see everything
  
          and::
  
              yagmail.set_logging(yagmail.logging.DEBUG, 'somelocalfile.log')
  
          lastly, a log_level of :py:class:`None` will make sure there is no I/O.