Read the class visibility
```ebnf
class_scope ::= (T_FINAL | T_ABSTRACT)?
```
function() {
    const result = this.token;
    if (result == this.tok.T_FINAL) {
      this.next();
      return [0, 0, 2];
    } else if (result == this.tok.T_ABSTRACT) {
      this.next();
      return [0, 0, 1];
    }
    return [0, 0, 0];
  }