def swapped_cities(tour):
'''generator to create all possible variations where two cities have been swapped'''
for i,j in itertools2.all_pairs(len(tour)):
if i < j:
copy=tour[:]
copy[i],copy[j]=tour[j],tour[i]
yield copy
def reversed_sections(tour):
'''generator to return all possible variations where the section between two cities are swapped'''
for i,j in itertools2.all_pairs(len(tour)):
if i and j and i < j:
copy=tour[:]
copy[i:j+1]=reversed(tour[i:j+1])
yield copy
