Called by ``__init__()`` to initialise the caches for a helper instance.
        It is also called by Django's ``setting_changed`` signal to clear the
        caches when changes to settings are made.

        Although it requires slightly more memory, separate dictionaries are
        used for raw values, models, modules and other objects to help with
        lookup performance for each type.

def reset_caches(self, **kwargs):
        """
        Called by ``__init__()`` to initialise the caches for a helper instance.
        It is also called by Django's ``setting_changed`` signal to clear the
        caches when changes to settings are made.

        Although it requires slightly more memory, separate dictionaries are
        used for raw values, models, modules and other objects to help with
        lookup performance for each type.
        """
        self._raw_cache = {}
        self._models_cache = {}
        self._modules_cache = {}
        self._objects_cache = {}