docs: def set(self, **kwargs):
          '''
          Override existing settings, taking precedence over both user settings
          object and default settings. Useful for specific runtime requirements,
          such as overriding PORT or HOST.
          '''
          for lower_key, value in kwargs.items():
              if lower_key.lower() != lower_key:
                  raise ValueError('Requires lowercase: %s' % lower_key)
              key = lower_key.upper()
              try:
                  getattr(self, key)
              except (AttributeError, ConfigurationError):
                  raise AttributeError('Cannot override %s' % key)
              self.overridden_settings[key] = value