```
import tensorflow as tf
import numpy as np
l = np.array([[[0.4,0.6],[0.1,0.9]],[[0.7,0.3],[0.8,0.2]]])
ll = tf.convert_to_tensor(l,dtype=tf.float32)
ppt = tf.reduce_mean(ll,2,keep_dims=True)
with tf.Session() as sess:
sess.run([init, init_local])
print(sess.run(ppt))
```

The result is:

[[[0.5] [0.5]] [[0.5] [0.5]]]