def move(self, state=None):
state = self.state if state is None else state<EOL>route = state<EOL>a = random.randint(self.locked_range, len(route) - <NUM_LIT:1>)<EOL>b = random.randint(self.locked_range, len(route) - <NUM_LIT:1>)<EOL>route[a], route[b] = route[b], route[a]<EOL>
Swaps two cities in the route.

        :type state: TSPState