def evaluate_marker(text, extra=None):
    """
    Evaluate a PEP 508 environment marker.
    Return a boolean indicating the marker result in this environment.
    Raise SyntaxError if marker is invalid.

    This implementation uses the 'pyparsing' module.
    """
    try:
        marker = packaging.markers.Marker(text)
        return marker.evaluate()
    except packaging.markers.InvalidMarker as e:
        raise SyntaxError(e) from e

    Evaluate a PEP 508 environment marker.
    Return a boolean indicating the marker result in this environment.
    Raise SyntaxError if marker is invalid.

    This implementation uses the 'pyparsing' module.
    
src/pkg_resources/__init__.py