class RuboCop::ConfigValidator

def reject_mutually_exclusive_defaults
  disabled_by_default = for_all_cops['DisabledByDefault']
  enabled_by_default = for_all_cops['EnabledByDefault']
  return unless disabled_by_default && enabled_by_default
  msg = 'Cops cannot be both enabled by default and disabled by default'
  raise ValidationError, msg
end