/// <summary> /// Determines whether the current set is a proper (strict) subset of a specified collection. /// </summary> /// <param name="other">The collection to compare to the current set.</param> /// <returns>true if the current set is a correct subset of other; otherwise, false.</returns> public bool IsProperSubsetOf(IEnumerable <T> other) { return(ImmutableHashSet <T> .IsProperSubsetOf(other, this.Origin)); }