public static bool IsKnown(this ILearnDirectClassSystemCode source) =>
source != null &&
!string.IsNullOrWhiteSpace(source.Code) &&
!source.Code.CaseInsensitiveEquals("NUL");
/// <summary>
/// Determines whether this instance is known.
/// </summary>
/// <param name="source">The source.</param>
/// <returns>
/// <c>true</c> if this instance is known; otherwise, <c>false</c>.
/// </returns>
public static bool IsKnown(this ILearnDirectClassSystemCode source) =>
It.Has(source) &&
It.Has(source.Code) &&
!source.Code.ComparesWith("NUL");
