Iterates over values in the set.
Add a group to this mask
The group to add
Add multiple groups to this mask
The groups to add
Remove all groups from this mask
Remove a group from this mask
The group to remove
Whether the group was removed from this mask
Returns an iterable of [v,v] pairs for every value
v in the set.
Check if a group is in this mask
The group to check
Whether the group is in this mask
Despite its name, returns an iterable of the values in the set,
Make this mask contain only the given groups
The items to add
Returns an iterable of values in the set.