code: def prepend(x: T, xs: Iterable[T]) -> Iterator[T]:
      
      return chain([x], xs)
docs: Prepend a value to an iterable.
  
      Parameters
      ----------
      x
          An element of type T.
      xs
          An iterable of elements of type T.
  
      Returns
      -------
      Iterator
          An iterator that yields *x* followed by elements of *xs*.
  
      Examples
      --------
  
      >>> from delphi.utils.fp import prepend
      >>> list(prepend(1, [2, 3]))
      [1, 2, 3]