AttributeError: 'builtin_function_or_method' object has no attribute 'tolist'

Question

import numpy as np
import tensorflow as tf
from flask import Flask,jsonify,render_template,request

from mnist import model

x= tf.placeholder("float",[None,784])
sess = tf.Session()

with tf.variable_scope("regression"):
    y1, variables= model.regression(x)
saver = tf.train.Saver(variables)
saver.restore(sess,"data/regression.ckpt")

with tf.variable_scope("convolutional"):
    keep_prob = tf.placeholder("float")
    y2 , variables = model.convolutional(x, keep_prob)

saver = tf.train.Saver(variables)
module_file =  tf.train.latest_checkpoint('data/convolutional.ckpt')


def regression(input):  # 如果要防止time报错就要把下面的函数
    return sess.run(y1, feed_dict={x: input}).flatten().tolist()


def convolutional(input):   #一直报错，先取消掉
   return sess.run(y2, feed_dict={x: input, keep_prob: 1.0}).flatten.tolist()
with tf.Session() as sess:
   sess.run(tf.global_variables_initializer())
   if module_file is not None:
      saver.restore(sess, module_file)
#saver.restore(sess,"data/convolutional.ckpt")



   app = Flask(__name__)


   @app.route('/api/mnist', methods=['POST'])
   def mnist():
       input = ((255 - np.array(request.json, dtype=np.uint8)) / 255.0).reshape(1, 784)
       output1 = regression(input)
       output2 = convolutional(input)
       return jsonify(results=[output1, output2])


   @app.route('/')
   def main():
       return render_template('index.html')


   if __name__ == "__main__":
       app.debug = True
       app.run(host="127.0.0.1", port=5000)