<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def format_expose(expose):
 """ Converts a port number or multiple port numbers, as used in the Dockerfile ``EXPOSE`` command, to a tuple. :param: Port numbers, can be as integer, string, or a list/tuple of those. :type expose: int | unicode | str | list | tuple :return: A tuple, to be separated by spaces before inserting in a Dockerfile. :rtype: tuple """

    if isinstance(expose, six.string_types):
        return expose,
    elif isinstance(expose, collections.Iterable):
        return map(six.text_type, expose)
    return six.text_type(expose),