docs: def cumsum(inlist):
      """
  Returns a list consisting of the cumulative sum of the items in the
  passed list.
  
  Usage:   lcumsum(inlist)
  """
      newlist = copy.deepcopy(inlist)
      for i in range(1, len(newlist)):
          newlist[i] = newlist[i] + newlist[i - 1]
      return newlist