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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_swagger(cls, pclass_for_definition, name, definition):
 """ Create a new ``_ClassModel`` from a single Swagger definition. :param pclass_for_definition: A callable like ``Swagger.pclass_for_definition`` which can be used to resolve type references encountered in the definition. :param unicode name: The name of the definition. :param definition: The Swagger definition to model. This will be a value like the one found at ``spec["definitions"][name]``. :return: A new model for the given definition. """

        return cls(
            name=name,
            doc=definition.get(u"description", name),
            attributes=cls._attributes_for_definition(
                pclass_for_definition,
                definition,
            ),
        )