set helpers

index.bs

@@ -393,6 +393,17 @@ To <dfn export>resume</dfn> given |name|, |id| and |parameters|:
 
 </div>
 
+<div algorithm>
+To <dfn for=set>create</dfn> a [=/set=], from a [=/list=] |input|:
+
+1. Let |result| be an empty [=/set=].
+
+1. For each [=list/item=] |item| in |input|, [=set/append=] |item| to |result|.
+
+1. Return |result|.
+
+</div>
+
 # Protocol # {#protocol}
 
 This section defines the basic concepts of the WebDriver BiDi
@@ -1897,13 +1908,13 @@ Issue: This needs to be generalized to work with realms too.
 <div algorithm="remote end steps for session.subscribe">
 The [=remote end steps=] with |session| and |command parameters| are:
 
-1. Let the |event names| be a [=/set=] containing |command parameters|["<code>events</code>"].
+1. Let the |event names| be [=set/create=] given |command parameters|["<code>events</code>"].
 
 1. Let |subscription navigables| be a [=/set=].
 
 1. Let |top-level traversable context ids| be a [=/set=].
 
-1. Let |input context ids| be a [=/set=] of |command parameters|[<code>contexts</code>].
+1. Let |input context ids| be [=set/create=] given |command parameters|[<code>contexts</code>].
 
 1. If |input context ids| is not empty: