Tensorflow を用いて、ネステロフ慣性最適化を実装してください．( 慣性は 0.9 )
N_optimizer = ##########
1. tf.train.MomentumNesteerov(learning_rate=learning_rate, momentum=0.9)
2. tf.train.MomentumOptimizer(learning_rate=learning_rate, momentum=0.9, use_nesterov=False)
3. tf.train.MomentumOptimizer(learning_rate=learning_rate, momentum=0.9, use_nesterov=True)