Hello I would like to create validation mixin or mixin template
which would return on error.
Something like this:
```
mixin template Validate(a, b)
{
if(a > b)
{
writeln("invalid input");
return false;
}
}
bool test(a,b)
{
mixin Validate!(a,b);
----
on valid code
----
return true;
}
```