# File lib/fog/aws/requests/efs/describe_mount_targets.rb, line 35
        def describe_mount_targets(options={})
          response = Excon::Response.new

          mount_targets = if id = options[:id]
                            if mount_target = self.data[:mount_targets][id]
                              [mount_target]
                            else
                              raise Fog::AWS::EFS::NotFound.new("Mount target does not exist.")
                            end
                          elsif file_system_id = options[:file_system_id]
                            self.data[:mount_targets].values.select { |mt| mt["FileSystemId"] == file_system_id }
                          else
                            raise Fog::AWS::EFS::Error.new("file system ID or mount target ID must be specified")
                          end

          mount_targets.each do |mount_target|
            mount_target['LifeCycleState'] = 'available'
            self.data[:mount_targets][mount_target["MountTargetId"]] = mount_target
          end

          response.body = {"MountTargets" => mount_targets}
          response
        end