Don't return fitness

src/individual.py

@@ -15,7 +15,6 @@ class Individual(object):
         y = self.y
         n = 9
         self.fitness = pow(15*x*y*(1-x)*(1-y)*sin(n*pi*x)*sin(n*pi*y), 2)
-        return self.fitness
 
     def crossover(self, spouse):
         temp = self.x

src/main.py

@@ -6,5 +6,3 @@ args.add_argument("pop", help="Population size", type=int)
 args = args.parse_args()
 
 pop = Population(10)
-
-print("%d" % pop.fitness_function())