@Nonnull
	public Collection<V> remove(K key) {
		Collection<V> collection = backing.remove(key);
		if (collection == null) {
			return Collections.emptyList();
		}
		return collection;
	}
Removes a collection of values.

@param key
		Key to remove.

@return Collection of removed values or an empty list, if none.
recaf-core/src/main/java/software/coley/recaf/util/MultiMap.java