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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 show_error(self, message):
 """ Send an error message to the active client. The new error will be displayed on any active GUI clients. Args: message (str):
 Plain-text message to display. Returns: None [] """

        assert isinstance(message, string_types)
        self.post('error', data=message)