code: def merge(a):
      """
      Merge Sort: split the list in half, and sort each half, then
      combine the sorted halves.
      """
      count = 0
      if len(a) > 1:
          midpoint = len(a) // 2
          b = a[:midpoint]
          c = a[midpoint:]
          count_b = merge(b)
          count_c = merge(c)
          result, count_a = _merge_lists(b, c)
          a[:] = result  # copy the result back into a.
          count = count_a + count_b + count_c
      return count
  
file_path: nltk/nltk/misc/sort.py
label_desc: Use image node_id 4 for calling a global function with example usage: merge(a) and returns: count