pub fn is_constant<EXTRA>(f: &crate::puppet_lang::builtin::BuiltinVariant<EXTRA>) -> bool {
match &f {
crate::puppet_lang::builtin::BuiltinVariant::Undef => true,
crate::puppet_lang::builtin::BuiltinVariant::Return(_) => true,
crate::puppet_lang::builtin::BuiltinVariant::Tag(_)
| crate::puppet_lang::builtin::BuiltinVariant::Require(_)
| crate::puppet_lang::builtin::BuiltinVariant::Include(_)
| crate::puppet_lang::builtin::BuiltinVariant::Realize(_)
| crate::puppet_lang::builtin::BuiltinVariant::Template(_)
| crate::puppet_lang::builtin::BuiltinVariant::CreateResources(_) => {
false
}
}
}