def remove_metadata_key(self, obj, key):
        """
        Removes the specified key from the object's metadata. If the key does
        not exist in the metadata, nothing is done.
        """
        meta_dict = {key: ""}
        return self.set_metadata(obj, meta_dict)
Removes the specified key from the object's metadata. If the key does
        not exist in the metadata, nothing is done.