Adding 2-opt algorithm to solve the Travelling Salesman Problem in Python

Question

I couldn't find any complete implementation of the 2-opt algorithm in Python so I am trying to add the missing parts in the this project..I want to get best solution.But in this project gives final route with cross path. To fix this I implement two opt algorithm to this code. But after all ,final route again with cross.It is two opt algorithm that i added to this source

I get this function from here:two-opt

def two_optt(self, route):
    best = route
    improved = True
    while improved:
        improved = False
        for i in range(1, len(route.route) - 2):
            for j in range(i + 1, len(route.route)):
                if j - i == 1: continue
                new_route=Route()
                new_route.route = route.route[:]
                new_route.recalc_rt_len()

                new_route.route[i:j] = route.route[j-1:i - 1:-1]  # this is the 2woptSwap
                new_route.recalc_rt_len()
                if new_route.length < best.length:
                    best = new_route

                    improved = True
            route=best

    best.recalc_rt_len()
    return best

I added this function into class GA and i called this function after mutate calling.I called it, like this in code part:`

    for route in descendant_pop.rt_pop:
        if random.random() < 0.3:
            self.mutate(route)
        self.two_optt(route) `

Again i get a solution with cross path. What should i do ? Is it where I add two opt function wrong, or where I call wrong?