Set ``Attr`` object and return it (if exists).

def removeNamedItem(self, item: Attr) -> Optional[Attr]:
        """Set ``Attr`` object and return it (if exists)."""
        from wdom.web_node import WdomElement
        if not isinstance(item, Attr):
            raise TypeError('item must be an instance of Attr')
        if isinstance(self._owner, WdomElement):
            self._owner.js_exec('removeAttribute', item.name)
        removed_item = self._dict.pop(item.name, None)
        if removed_item:
            removed_item._owner = self._owner
        return removed_item