ahhh ok, so if you define operators inside the class declaration, you must you the class-specific operators, e.g., 
```
class A {
bool operator<(const A& other) {
  return a < other.a;
}
};
```
vs.
```
class A {
// stuff
};
bool operator<(const A& l, const A& r) {
  return l.a < r.a;
}

```