[ADD] ModifiedTensorboard object has no attribute '_write_logs' 에러

https://pythonprogramming.net/training-deep-q-learning-dqn-reinforcement-learning-python-tutorial/

# ModifiedTensorboard 클래스에 다음 메소드 추가
   def _write_logs(self, logs, index):
        for name, value in logs.items():
            if name in ['batch', 'size']:
                continue
            summary = tf.Summary()
            summary_value = summary.value.add()
            summary_value.simple_value = value
            summary_value.tag = name
            self.writer.add_summary(summary, index)
        self.writer.flush()