Collection of objects represented as hash keys
QuantHash represents a set of objects, represented as the keys of a
Hash. When asked to behave as a list it ignores its
.values and returns only
.keys (possibly replicated by weight in the case of bag types). For any
.total methods returns the current sum of the values.
All standard QuantHash containers have a default value that is false (such as
Bool::False), and keep around only those entries with non-default values, automatically deleting any entry if its value goes to that (false) default value.