Inconsistency in Online DFS AGENT(aima3e Fig.4.21) pseudocode and python implementation

[masterchef2209]

The pseudocode for Online DFS Agent contains line else a ← an action b such that result[s', b] = POP(unbacktracked[s']). I see that it is not consistent with python implementation here.

else:
                    # else a <- an action b such that result[s', b] = POP(unbacktracked[s'])
                    unbacktracked_pop = self.unbacktracked.pop(s1)
                    for (s, b) in self.result.keys():
                        if self.result[(s, b)] == unbacktracked_pop:
                            self.a = b
                            break

which implies we are getting an action where result[s,b](result of s instead of s') =POP(unbacktracked[s'])