message: Broken param guard.
diff: @@ -29,7 +29,7 @@ namespace Hyperledger.Indy.Utils
  /// <exception cref="ArgumentException">Thrown if param was null or contained whitespace.</exception>
  public static void NotNullOrWhiteSpace(string param, string paramName)
  {
  - if (param == null)
  + if (string.IsNullOrWhiteSpace(param))
  throw new ArgumentException("A value must be provided.", paramName);
  }
  }
  