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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 handle_result(self, result, error):
 """ The result has been received :param result: Call result :param error: Error message """

        if not self._error and not self._result:
            # Store results, if not already set
            self._error = error
            self._result = result

        # Unlock the call
        self._event.set()