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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 __download(self, url, loaded_schemata, options):
 """Download the schema."""

        try:
            reader = DocumentReader(options)
            d = reader.open(url)
            root = d.root()
            root.set("url", url)
            return self.schema.instance(root, url, loaded_schemata, options)
        except TransportError:
            msg = "import schema (%s) at (%s), failed" % (self.ns[1], url)
            log.error("%s, %s", self.id, msg, exc_info=True)
            raise Exception(msg)