using System.Linq.Expressions; // ReSharper disable once CheckNamespace namespace System.Linq { public static class Queryable { /// /// Makes a where filtering, if it is not null. /// public static IQueryable WhereOrDefault(this IQueryable source, Expression>? predicate) { if (source == null) throw new ArgumentNullException(nameof(source)); return predicate is null ? source : source.Where(predicate); } } }