code: def dispatch(t):
      
  
      if not t:
          return t
      else:
          t = list(t)
  
      # Make sure they're passing in something.
      assert len(t) >= 2
  
      # If only two items are passed in, assume HTTPBasic.
      if (len(t) == 2):
          t.insert(0, 'basic')
  
      # Allow built-in string referenced auths.
      if isinstance(t[0], basestring):
          if t[0] in ('basic', 'forced_basic'):
              t[0] = http_basic
          elif t[0] in ('digest',):
              t[0] = http_digest
  
      # Return a custom callable.
      return (t[0], tuple(t[1:]))
docs: Given an auth tuple, return an expanded version.