Put a value in the set of values mapped to the key.
Returns the set of values associated with the given key.
Returns a set of all keys that the given value belongs to the set of values
associated with them.
Clears that map. The map becomes empty after calling this method.
Returns true if there at least one key that the given value belongs to its set.
Creates a copy of the map. Each set is actually copied, such that the set
associated to a key in the
true if the map is empty.
Removes the specified key. For each value that is in the set associated to that
key, such that that
Removes that value. For any key that that value belongs to the set of values
associated with it, the