Loads a specific fixture from a fixture file, optionally passing it through
    a normalization function.

def load_fixture(fixture_path: str,
                 fixture_key: str,
                 normalize_fn: Callable[..., Any]=identity) -> Dict[str, Any]:
    """
    Loads a specific fixture from a fixture file, optionally passing it through
    a normalization function.
    """
    file_fixtures = load_json_fixture(fixture_path)
    fixture = normalize_fn(file_fixtures[fixture_key])
    return fixture