def METHOD_NAME(env: str):
    """Sets up a mocked GcsClient.
    Args:
        env:  Name of the Nomulus environment.
    Returns:
        A GcsClient instance and two mocked blobs representing the two schema
        tag file and version map file on GCS.
    """
    schema_tag_blob = mock.MagicMock()
    schema_tag_blob.download_as_text.return_value = 'tag\n'
    version_map_blob = mock.MagicMock()
    blobs_by_name = {
        f'nomulus.{env}.versions': version_map_blob,
        f'sql.{env}.tag': schema_tag_blob
    }
    bucket = mock.MagicMock()
    bucket.get_blob.side_effect = lambda blob_name: blobs_by_name[blob_name]
    google_client = mock.MagicMock()
    google_client.get_bucket.return_value = bucket
    gcs_client = gcs.GcsClient('project', google_client)
    return (gcs_client, schema_tag_blob, version_map_blob)