title: Celery 'module' object has no attribute 'app' when using Python 3
body: <p>I am going through Celery tutorial. They are using Python2 and I am trying to implement the same using python3.</p>
  
  <p>I have 2 files:</p>
  
  <p><strong>celery_proj.py</strong> :</p>
  
  <pre><code>from celery import Celery
  
  app = Celery(
      'proj', broker='amqp://', backend='amqp://', include=['proj.tasks'])
  
  app.conf.update(Celery_TAST_RESULT_EXPIRES=3600,)
  
  if __name__ == '__main__':
      app.start()
  </code></pre>
  
  <p>and <strong>tasks.py</strong> :</p>
  
  <pre><code>from celery_proj import app
  
  
  @app.task
  def add(x, y):
      return x + y
  
  
  @app.task
  def mul(x, y):
      return x * y
  
  
  @app.task
  def xsum(numbers):
      return sum(numbers)
  </code></pre>
  
  <p>When I try to run <code>celery -A proj worker -l info</code> I am getting :</p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/local/lib/python3.4/dist-packages/celery/app/utils.py", line 235, in find_app
      found = sym.app
  AttributeError: 'module' object has no attribute 'app'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/usr/local/bin/celery", line 11, in &lt;module&gt;
      sys.exit(main())
    File "/usr/local/lib/python3.4/dist-packages/celery/__main__.py", line 30, in main
      main()
    File "/usr/local/lib/python3.4/dist-packages/celery/bin/celery.py", line 81, in main
      cmd.execute_from_commandline(argv)
    File "/usr/local/lib/python3.4/dist-packages/celery/bin/celery.py", line 769, in execute_from_commandline
      super(CeleryCommand, self).execute_from_commandline(argv)))
    File "/usr/local/lib/python3.4/dist-packages/celery/bin/base.py", line 309, in execute_from_commandline
      argv = self.setup_app_from_commandline(argv)
    File "/usr/local/lib/python3.4/dist-packages/celery/bin/base.py", line 469, in setup_app_from_commandline
      self.app = self.find_app(app)
    File "/usr/local/lib/python3.4/dist-packages/celery/bin/base.py", line 489, in find_app
      return find_app(app, symbol_by_name=self.symbol_by_name)
    File "/usr/local/lib/python3.4/dist-packages/celery/app/utils.py", line 240, in find_app
      found = sym.celery
  AttributeError: 'module' object has no attribute 'celery'
  </code></pre>
  
  <p>What am I doing wrong and how to fix this?</p>