jstraitlets.py 文件源码

def validate(self, obj, value):
        if self.allow_undefined and value is undefined:
            return value
        try:
            self.not_this.validate(obj, value)
        except T.TraitError:
            return value
        else:
            self.error(obj, value)



##########################################################################
# Visitor Pattern
#
# This implements to_dict() and from_dict() using an External Visitor Pattern
# built for the above classes.