public static HashSet <T> ToHashSet <T>([NotNull] this IEnumerable <T> source, [NotNull] IEqualityComparer <T> comparer)
{
source.GuardNotNull(nameof(source));
comparer.GuardNotNull(nameof(comparer));
return(new HashSet <T>(source, comparer));
}
public static bool IsEither <T>(this T obj, IEnumerable <T> variants,
IEqualityComparer <T> comparer)
{
variants.GuardNotNull(nameof(variants));
comparer.GuardNotNull(nameof(comparer));
return(variants.Contains(obj, comparer));
}
