code: def format(self, s, pretty=None, expand=None):
          
          if pretty is None:
              pretty = self.format_pretty
          if expand is None:
              expand = self.format_expand
  
          formatter = ObjectStringFormatter(self, pretty=pretty, expand=expand)
          return formatter.format(s)
docs: Format a string.
  
          Args:
              s (str): String to format, eg "hello {name}"
              pretty (bool): If True, references to non-string attributes such as
                  lists are converted to basic form, with characters such as
                  brackets and parenthesis removed. If None, defaults to the
                  object's 'format_pretty' attribute.
              expand (`StringFormatType`): Expansion mode. If None, will default
                  to the object's 'format_expand' attribute.
  
          Returns:
              The formatting string.