protected bool ValidCompare(ExpressionValue expressionValue, ExpressionOperator op)
 {
     return(ExpressionOperators.Comparison.Contains(op) && CompatibleOperators.Contains(op));
 }
 protected bool ValidCombine(ExpressionValue expressionValue, ExpressionOperator op)
 {
     return(CompatibleTypes.Contains(expressionValue.ExpressionType) && CompatibleOperators.Contains(op));
 }