maximum sum of sub segmentation

def max_sum_of_sub_seg(a):
 cur_max_sum=0
 cur_item_val=0
 for item in a:
  if cur_item_val <0:
   cur_item_val = item
  else:
   cur_item_val = cur_item_val +item
  if cur_max_sum < cur_item_val:
   cur_max_sum = cur_item_val
 return cur_max_sum

print max_sum_of_sub_seg([-2,11,-4,13,-5,-2])