mergesort

#!/usr/bin/python

list  = [6,7,5,8,3,1,2,4]

def divide(list):
    if len(list) <= 1:
        return list
    else:
        mid = int(len(list)/2)
        flist = divide(list [:mid])
        llist = divide(list [mid:])
        return merge(flist,llist)


def merge(flist,llist):
    i = j = 0; list =[]
    while i<len(flist) and j < len(llist):
       if flist[i] < llist[j]:
            list.append(flist[i])
            i += 1
           else:
            list.append(llist[j])
            j += 1
def main(list):
    return divide(list)

print main(list)



################## END of CODE ###################
#====================================================================================================#

The output is:
Traceback (most recent call last):
  File "./code/python/personal/merge sort", line 27, in <module>
    print main(list)
  File "./code/python/personal/merge sort", line 25, in main
    return divide(list)
  File "./code/python/personal/merge sort", line 10, in divide
    flist = divide(list [:mid])
  File "./code/python/personal/merge sort", line 12, in divide
    return merge(flist,llist)
  File "./code/python/personal/merge sort", line 17, in merge
    while i<len(flist) and j < len(llist):
TypeError: object of type 'NoneType' has no len()