@staticmethod
def nonNegativeIntOrNone(value):
    """
        If value is None or negative, return None, otherwise return int(value).
        This is used in "setter" methods to ensure the correct type.

        :param int value: The value to check.
        :return: value or None.
        :rtype: int
        """
    return None if value == None or value < 0 else int(value)
