code: def max_element (elements, ordered = None):
      
      assert is_iterable(elements)
      assert callable(ordered) or ordered is None
      if not ordered: ordered = operator.lt
  
      max = elements [0]
      for e in elements [1:]:
          if ordered (max, e):
              max = e
  
      return max
docs: Returns the maximum number in 'elements'. Uses 'ordered' for comparisons,
          or '<' is none is provided.