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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def delete_repository_tag(self, project_id, tag_name):
 """ Deletes a tag of a repository with given name. :param project_id: The ID of a project :param tag_name: The name of a tag :return: Dictionary containing delete tag :raise: HttpError: If invalid response returned """

        return self.delete('/projects/{project_id}/repository/tags/{tag_name}'.format(
            project_id=project_id, tag_name=tag_name))