def coerce_tuple(item):
    """Return item converted to tuple if not already tuple.

    :param Union[str, IKey, Iterable] item: item to coerce to tuple.
    :returns: coerced value of item as tuple.
    :rtype: Tuple[Any].

    .. Usage::

        >>> coerce_tuple('test')
        ('test',)

        >>> coerce_tuple(('test', 'two'))
        ('test', 'two')

    """
    if isinstance(item, (list, tuple)):
        return tuple(item)
    return (item,) if item is not None else None