code: def promote16(u, fn=None, *args, **kwargs):
      r
  
      dtype = np.float32 if u.dtype == np.float16 else u.dtype
      up = np.asarray(u, dtype=dtype)
      if fn is None:
          return up
      else:
          v = fn(up, *args, **kwargs)
          if isinstance(v, tuple):
              vp = tuple([np.asarray(vk, dtype=u.dtype) for vk in v])
          else:
              vp = np.asarray(v, dtype=u.dtype)
          return vp
docs: r"""
      Utility function for use with functions that do not support arrays
      of dtype ``np.float16``. This function has two distinct modes of
      operation. If called with only the `u` parameter specified, the
      returned value is either `u` itself if `u` is not of dtype
      ``np.float16``, or `u` promoted to ``np.float32`` dtype if it is. If
      the function parameter `fn` is specified then `u` is conditionally
      promoted as described above, passed as the first argument to
      function `fn`, and the returned values are converted back to dtype
      ``np.float16`` if `u` is of that dtype. Note that if parameter `fn`
      is specified, it may not be be specified as a keyword argument if it
      is followed by any non-keyword arguments.
  
      Parameters
      ----------
      u : array_like
        Array to be promoted to np.float32 if it is of dtype ``np.float16``
      fn : function or None, optional (default None)
        Function to be called with promoted `u` as first parameter and
        \*args and \*\*kwargs as additional parameters
      *args
        Variable length list of arguments for function `fn`
      **kwargs
        Keyword arguments for function `fn`
  
      Returns
      -------
      up : ndarray
        Conditionally dtype-promoted version of `u` if `fn` is None,
        or value(s) returned by `fn`, converted to the same dtype as `u`,
        if `fn` is a function