    # File lib/fog/aws/requests/compute/modify_volume_attribute.rb, line 35
            def modify_volume_attribute(volume_id=nil, auto_enable_io_value=false)
              response = Excon::Response.new
              if volume = self.data[:volumes][volume_id]
                response.status = 200
                response.body = {
                  'requestId' => Fog::AWS::Mock.request_id,
                  'return'    => true
                }
                response
              else
                raise Fog::Compute::AWS::NotFound.new("The volume '#{volume_id}' does not exist.")
              end
            end