code: def discover(app, module_name=None):
      
      from permission.compat import import_module
      from permission.compat import get_model
      from permission.conf import settings
      from permission.utils.logics import add_permission_logic
  
      variable_name = settings.PERMISSION_AUTODISCOVER_VARIABLE_NAME
      module_name = module_name or settings.PERMISSION_AUTODISCOVER_MODULE_NAME
  
      # import the module
      m = import_module('%s.%s' % (app, module_name))
  
      # check if the module have PERMISSION_LOGICS variable
      if hasattr(m, variable_name):
          # apply permission logics automatically
          permission_logic_set = getattr(m, variable_name)
          for model, permission_logic in permission_logic_set:
              if isinstance(model, six.string_types):
                  # convert model string to model instance
                  model = get_model(*model.split('.', 1))
              add_permission_logic(model, permission_logic)
docs: Automatically apply the permission logics written in the specified
      module.
  
      Examples
      --------
      Assume if you have a ``perms.py`` in ``your_app`` as::
  
          from permission.logics import AuthorPermissionLogic
          PERMISSION_LOGICS = (
              ('your_app.your_model', AuthorPermissionLogic),
          )
  
      Use this method to apply the permission logics enumerated in
      ``PERMISSION_LOGICS`` variable like:
  
          >>> discover('your_app')