Class method to check every settings.

        Will raise an ``ImproperlyConfigured`` exception with explanation.

def check(cls):
        """
        Class method to check every settings.

        Will raise an ``ImproperlyConfigured`` exception with explanation.
        """
        if cls == AppSettings:
            return None

        exceptions = []
        for setting in cls.settings.values():
            try:
                setting.check()
            # pylama:ignore=W0703
            except Exception as e:
                exceptions.append(str(e))
        if exceptions:
            raise ImproperlyConfigured("\n".join(exceptions))