traitlets.py 文件源码

def trait_code(self):
        """Create the trait code for the given schema"""
        kwargs = {}
        if self.description:
            kwargs['help'] = textwrap.shorten(self.description, 70)

        # TODO: handle multiple matches with an AllOf()
        for TraitExtractor in self.trait_extractors:
            trait_extractor = TraitExtractor(self)
            if trait_extractor.check():
                return trait_extractor.trait_code(**kwargs)
        else:
            raise ValueError("No recognized trait code for schema with "
                             "keys {0}".format(tuple(self.schema.keys())))