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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 begin(self, service_endpoint):
 """Create an AuthRequest object for the specified service_endpoint. This method will create an association if necessary."""

        if self.store is None:
            assoc = None
        else:
            assoc = self._getAssociation(service_endpoint)

        request = AuthRequest(service_endpoint, assoc)
        request.return_to_args[self.openid1_nonce_query_arg_name] = mkNonce()

        if request.message.isOpenID1():
            request.return_to_args[self.openid1_return_to_identifier_name] = \
                request.endpoint.claimed_id

        return request