oneOf

enum TestEnum
{
    ONE = 1,
    TWO = 2,
    FOUR = 4
}

assert( !oneOf!TestEnum(0) );
assert(  oneOf!TestEnum(1) );
assert(  oneOf!TestEnum(2) );
assert( !oneOf!TestEnum(3) );
assert(  oneOf!TestEnum(4) );
assert( !oneOf!TestEnum(5) );