'Loads the app with the provided fully qualified name, and returns the
model module.'

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 (not module_has_submodule(app_module, 'models')):
            return None
        elif 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)
    return models
