'Create the encoding layer of the network.
Returns
self'

def _create_encode_layer(self):

    with tf.name_scope('encoder'):
        activation = tf.add(tf.matmul(self.input_data, self.W_), self.bh_)
        if self.enc_act_func:
            self.encode = self.enc_act_func(activation)
        else:
            self.encode = activation
        return self
