我正在从此处的文档中遵循flask-cors教程：https
://pypi.python.org/pypi/Flask-Cors

但是当我在树莓派上安装它并运行我的python应用程序时，出现此错误

Traceback (most recent call last): File "app.py", line 3, in <module> from flask_cors import CORS, cross_origin ImportError: No module named 'flask_cors'

这是我的python脚本：

from flask import Flask
from Main import main
from flask_cors import CORS, cross_origin    
app = Flask(__name__)
CORS(app)
main = main()

@app.route('/turn' ,methods=['GET', 'OPTIONS'])
def index():
  return main.turn()

if __name__ == '__main__': 
  app.run(debug=True, host='0.0.0.0')