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)

    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.
    
stackoverflow/venv/lib/python3.6/site-packages/pip-19.0.3-py3.6.egg/pip/_vendor/pkg_resources/__init__.py