def error_response(error = {})
status = error[:status] || options[:default_status]
message = error[:message] || options[:default_message]
headers = { Grape::Http::Headers::CONTENT_TYPE => content_type }
headers.merge!(error[:headers]) if error[:headers].is_a?(Hash)
backtrace = error[:backtrace] || error[:original_exception] && error[:original_exception].backtrace || []
original_exception = error.is_a?(Exception) ? error : error[:original_exception] || nil
rack_response(format_message(message, backtrace, original_exception), status, headers)
end