old_contents: def one(iterable):
      """
      Return the object in the given iterable that evaluates to True.
  
      If the given iterable has more than one object that evaluates to True,
      or if there is no object that fulfills such condition, return False.
  
      >>> one((True, False, False))
      True
      >>> one((True, False, True))
      False
      >>> one((0, 0, 'a'))
      'a'
      >>> one((0, False, None))
      False
      >>> one((True, True))
      False
      >>> bool(one(('', 1)))
      True
      """
      the_one = False
      for i in iterable:
          if i:
              if the_one:
                  return False
              the_one = i
      return the_one
  
  
  if __name__ == "__main__":
      import doctest
      doctest.testmod()
  
new_contents: def one(iterable):
      """
      Return the object in the given iterable that evaluates to True.
  
      If the given iterable has more than one object that evaluates to True,
      or if there is no object that fulfills such condition, return False.
  
          >>> one((True, False, False))
          True
          >>> one((True, False, True))
          False
          >>> one((0, 0, 'a'))
          'a'
          >>> one((0, False, None))
          False
          >>> one((True, True))
          False
          >>> bool(one(('', 1)))
          True
      """
      the_one = False
      for i in iterable:
          if i:
              if the_one:
                  return False
              the_one = i
      return the_one
  
  
  if __name__ == "__main__":
      import doctest
      doctest.testmod()
  
subject: indent code in docstring