Is this point feasible?

You will write three small functions that test points against the rules of a feasible region. The checker tests them on many rules and points.

The idea. A rule is a tuple (a, b, sign, c), which stands for $ax + by$ compared with $c$. The sign is the text "<=" or ">=". A point is feasible if $x \ge 0$, $y \ge 0$ and it obeys every rule.

Your tasks.

1. Finish satisfies(rule, x, y). Return True if the point obeys that one rule.
2. Finish is_feasible(rules, x, y). Return True if $x \ge 0$, $y \ge 0$ and the point obeys every rule.
3. Finish count_points(rules, n). Count the feasible points with whole-number coordinates from 0 to n.