val list_concat_map : ?sep:'a -> f:('b -> 'a list) -> 'b list -> 'a list
val list_concat_map_list_sep : sep:'a list -> f:('b -> 'a list) -> 'b list -> 'a list
val optional_code : [< Html_types.code_content_fun ] Html.elt Html.list_wrap -> [> Html_types.code ] Html.elt list