code: def tree_statistics(tree):
      
      all_elements = tree.findall('//')
      tag_counter = defaultdict(int)
      for element in all_elements:
          tag_counter[element.tag] += 1
      for (tag, counts) in tag_counter.items():
          print "{0}: {1}".format(tag, counts)
docs: prints the types and counts of elements present in a SaltDocument tree,
      e.g.::
  
          layers: 3
          sDocument: 1
          nodes: 252
          labels: 2946
          edges: 531