def METHOD_NAME(self, citation_data):
    """Get the metadata file."""
    if not citation_data:
        return {}
    citation_schema = current_app.config.get("GITHUB_CITATION_METADATA_SCHEMA")
    assert isinstance(citation_schema, Schema), _(
        "Citation schema is needed to load citation metadata."
    )
    data = citation_schema().load(citation_data)
    return data