def load_app(self, app_name, can_postpone=False):
        self.handled[app_name] = None
        self.nesting_level += 1
        app_module = import_module(app_name)
        try:
            models = import_module('.models', app_name)
        except ImportError:
            self.nesting_level -= 1
            # If the app doesn't have a models module, we can just ignore the
            # ImportError and return no models for it.
            if not module_has_submodule(app_module, 'models'):
                return None
            # But if the app does have a models module, we need to figure out
            # whether to suppress or propagate the error. If can_postpone is
            # True then it may be that the package is still being imported by
            # Python and the models module isn't available yet. So we add the
            # app to the postponed list and we'll try it again after all the
            # recursion has finished (in populate). If can_postpone is False
            # then it's time to raise the ImportError.
            else:
                if can_postpone:
                    self.postponed.append(app_name)
                    return None
                else:
                    raise

        self.nesting_level -= 1
        if models not in self.app_store:
            self.app_store[models] = len(self.app_store)
            self.app_labels[self._label_for(models)] = models
        return models
Returns the canonical form of the given identity key.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/db/models/loading.py/AppCache.load_app--crossover with--dataset/ETHPy150Open viewfinderco/viewfinder/backend/db/identity.py/Identity.Canonicalize