Values.StepsSourceval to_value :
Step.t list ->
[> `List of
[> `Structure of
(string
* [> `Enum of string
| `Map of
([> `String of ThumbnailName.t ]
* [> `String of ThumbnailUrl.t ])
list
| `String of StepName.t
| `Timestamp of StartTime.t ])
list ]
list ]