title: Flask "(" unexpected error when using gunicorn
body: <p>I tried to deploy my flask app using gcloud, gunicorn.
  But when I wrote the app.yaml like below, it didn't work.</p>
  
  <p>Here is my app.yaml file.</p>
  
  <pre><code>runtime: python
  env: flex
  entrypoint: gunicorn -b :$PORT flask_todo:create_app
  
  runtime_config:
    python_version: 3
  
  manual_scaling:
    instances: 1
  resources:
    cpu: 1
    memory_gb: 0.5
    disk_size_gb: 10
  </code></pre>
  
  <p><strong>init</strong>.py file</p>
  
  <pre><code>import os
  from flask import Flask,render_template,request,url_for,redirect
  from . import db
  
  
  def create_app(test_config=None):
      app = Flask(__name__, instance_relative_config=True)
      app.config.from_mapping(
          SECRET_KEY='dev',
          DATABASE=os.path.join(app.instance_path, 'flaskr.sqlite'),
      )
  
      if test_config is None:
          app.config.from_pyfile('config.py', silent=True)
  
      else:
          app.config.from_mapping(test_config)
  
  
      try:
          os.makedirs(app.instance_path)
  
      except OSError:
          pass
      return app
  </code></pre>
  
  <p>flask_todo    #this is where I cd to and run gunicorn flask_todo:create_app</p>
  
  <pre><code>flask_todo
  --db.py
  --__init__.py
  --app.yaml
  --requirements.txt
  </code></pre>
  
  <p>What is the reason? Please help me..</p>