class Grape::Validations::Validators::AllowBlankValidator

def validate_param!(attr_name, params)
  return if (options_key?(:value) ? @option[:value] : @option) || !params.is_a?(Hash)
  value = params[attr_name]
  value = value.scrub if value.respond_to?(:scrub)
  return if value == false || value.present?
  raise Grape::Exceptions::Validation.new(params: [@scope.full_name(attr_name)], message: message(:blank))
end