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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 transform_external(self, external_url):
 """ Turns an external URL into a Filestack Transform object *returns* [Filestack.Transform] ```python from filestack import Client, Filelink client = Client("API_KEY") transform = client.transform_external('http://www.example.com') ``` """

        return filestack.models.Transform(apikey=self.apikey, security=self.security, external_url=external_url)