docs: 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))