Return the style of *style_type* matching *style_id*.

        Returns the default for *style_type* if *style_id* is not found or is |None|, or
        if the style having *style_id* is not of *style_type*.

def get_by_id(self, style_id, style_type):
        """Return the style of *style_type* matching *style_id*.

        Returns the default for *style_type* if *style_id* is not found or is |None|, or
        if the style having *style_id* is not of *style_type*.
        """
        if style_id is None:
            return self.default(style_type)
        return self._get_by_id(style_id, style_type)