code: def get_style_id(self, style_or_name, style_type):
          
          if style_or_name is None:
              return None
          elif isinstance(style_or_name, BaseStyle):
              return self._get_style_id_from_style(style_or_name, style_type)
          else:
              return self._get_style_id_from_name(style_or_name, style_type)
docs: Return the id of the style corresponding to *style_or_name*, or
          |None| if *style_or_name* is |None|. If *style_or_name* is not
          a style object, the style is looked up using *style_or_name* as
          a style name, raising |ValueError| if no style with that name is
          defined. Raises |ValueError| if the target style is not of
          *style_type*.