title: namedtuple TypeError count of positional arguments
body: <p>Why does the TypeError message indicate 3 positional arguments if the namedtuple only calls for two?  Why does it say that 4 were given?</p>
  
  <pre><code>from collections import namedtuple
  Transition = namedtuple('Transition', ('one', 'two'))
  a = Transition(1,2,3)
  #TypeError: __new__() takes 3 positional arguments but 4 were given
  </code></pre>