Warning: CHC: Division by zero happens here.
Counterexample:
arr = []
a = 0
x = 0

Transaction trace:
test.constructor()
State: arr = []
test.f(0, 1)
 --> model_checker_targets_div_by_zero_chc/input.sol:9:3:
  |
9 | 		2 / x;
  | 		^^^^^
