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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 setup(self, helper=None, **create_kwargs):
 """ Setup this resource so that is ready to be used in a test. If the resource has already been created, this call does nothing. For most resources, this just involves creating the resource in Docker. :param helper: The resource helper to use, if one was not provided when this resource definition was created. :param **create_kwargs: Keyword arguments passed to :meth:`.create`. :returns: This definition instance. Useful for creating and setting up a resource in a single step:: volume = VolumeDefinition('volly').setup(helper=docker_helper) """

        if self.created:
            return

        self.set_helper(helper)
        self.create(**create_kwargs)
        return self