human
Complete this python program:
def did_you_mean_units(s, all_units, deprecated_units, format_decomposed):
assistant
#Here is the Python code you requested.

    """A wrapper around `astropy.utils.misc.did_you_mean` that deals with
    the display of deprecated units.
    Parameters
    s : str
    The invalid unit string
    all_units : dict
    A mapping from valid unit names to unit objects.
    deprecated_units : sequence
    The deprecated unit names
    format_decomposed : callable
    A function to turn a decomposed version of the unit into a
    string.  Should return `None` if not possible
    Returns
    msg : str
    A string message with a list of alternatives, or the empty
    string.
    """
    def fix_deprecated(x):
        if (x in deprecated_units):
            results = [(x + u'    (deprecated)')]
            decomposed = _try_decomposed(all_units[x], format_decomposed)
            if (decomposed is not None):
                results.append(decomposed)
            return results
        return (x,)
    return did_you_mean(s, all_units, fix=fix_deprecated)