fast_insert(JMLType elem) Returns a new set that contains all the elements of this and
also the given argument, assuming the argument is not in the set.
public boolean
has(JMLType elem) Is the argument ".equals" to one of the
values in theSet.
Returns a new set that contains all the elements of this and
also the given argument, assuming the argument is not in the set.
See Also:JMLValueSet.insert(JMLType)