def _execute(self, *args: str, **kwargs) -> tuple:
        '''Execute command.'''
        process = self.execute(
            args=args, options=merge_dict(self.options, kwargs))
        command = ' '.join(process.args)
        if self._dev:
            output, error = process.communicate()
            print(
                "Debug Information",
                "Command: {!r}".format(command),
                "Output: {!r}".format(output.encode('utf-8')),
                "Error: {!r}".format(error.encode('utf-8')),
                sep='\n', end='\n{}\n'.format('=' * 80)
            )
        return process.communicate()
Execute command.