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