Return a fully-qualified key_ring string.

def key_ring_path(cls, project, location, key_ring):
        """Return a fully-qualified key_ring string."""
        return google.api_core.path_template.expand(
            "projects/{project}/locations/{location}/keyRings/{key_ring}",
            project=project,
            location=location,
            key_ring=key_ring,
        )