def verifyJobTreeOptions(options):
    """ verifyJobTreeOptions() returns None if all necessary values
    are present in options, otherwise it raises an error.
    It can also serve to validate the values of the options.
    """
    required = ['logLevel', 'batchSystem', 'jobTree']
    for r in required:
        if r not in vars(options):
            raise RuntimeError(
                'Error, there is a missing option (%s) from the jobTree Stack, did you remember to call Stack.addJobTreeOptions()?'
                 % r)
    if options.jobTree is None:
        raise RuntimeError('Specify --jobTree')
