def invalid_marker(text):
    """
    Validate text as a PEP 508 environment marker; return an exception
    if invalid or False otherwise.
    """
    try:
        evaluate_marker(text)
    except SyntaxError as e:
        e.filename = None
        e.lineno = None
        return e
    return False

    Validate text as a PEP 508 environment marker; return an exception
    if invalid or False otherwise.
    
product/gradle-plugin/src/main/python/pkg_resources/__init__.py