@classmethod
def addValidator(klass, func):
    """
        Add a function to the given classes validation list.

        @param klass: The Class to add the validator to.
        @param func: A function that accepts a single parameter that is the object
        to test for validity.  If the object is invalid, then this function should
        add errors to it's C{errors} property.

        @see: L{Errors}
        """
    klass.VALIDATIONS = klass.VALIDATIONS + [func]
