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Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def __fetch(self, url):
 """ Fetch document content from an external source. The document content will first be looked up in the registered document store, and if not found there, downloaded using the registered transport system. Before being returned, the fetched document content first gets processed by all the registered 'loaded' plugins. @param url: A document URL. @type url: str. @return: A file pointer to the fetched document content. @rtype: file-like """

        content = None
        store = self.options.documentStore
        if store is not None:
            content = store.open(url)
        if content is None:
            request = suds.transport.Request(url)
            fp = self.options.transport.open(request)
            try:
                content = fp.read()
            finally:
                fp.close()
        ctx = self.plugins.document.loaded(url=url, document=content)
        content = ctx.document
        sax = suds.sax.parser.Parser()
        return sax.parse(string=content)