$  celery -A app.tasks worker
Traceback (most recent call last):
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/bin/celery", line 11, in <module>
    sys.exit(main())
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/__main__.py", line 30, in main
    main()
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/celery.py", line 81, in main
    cmd.execute_from_commandline(argv)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/celery.py", line 769, in execute_from_commandline
    super(CeleryCommand, self).execute_from_commandline(argv)))
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/base.py", line 305, in execute_from_commandline
    argv = self.setup_app_from_commandline(argv)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/base.py", line 465, in setup_app_from_commandline
    self.app = self.find_app(app)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/base.py", line 485, in find_app
    return find_app(app, symbol_by_name=self.symbol_by_name)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/app/utils.py", line 229, in find_app
    sym = symbol_by_name(app, imp=imp)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/bin/base.py", line 488, in symbol_by_name
    return symbol_by_name(name, imp=imp)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/kombu/utils/__init__.py", line 92, in symbol_by_name
    module = imp(module_name, package=package, **kwargs)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib/python3.4/site-packages/celery/utils/imports.py", line 101, in import_from_cwd
    return imp(module, package=package)
  File "/home/rumanekm/workspace/MartinRumanek/InstantniKnihovna/IK/lib64/python3.4/importlib/__init__.py", line 109, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 2254, in _gcd_import
  File "<frozen importlib._bootstrap>", line 2237, in _find_and_load
  File "<frozen importlib._bootstrap>", line 2224, in _find_and_load_unlocked
ImportError: No module named 'app'