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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def remove_apppool(name):
    # Remove IIS AppPool
    '''
    Remove an IIS application pool.

    :param str name: The name of the IIS application pool.

    Usage:

    .. code-block:: yaml

        defaultapppool-remove:
            win_iis.remove_apppool:
                - name: DefaultAppPool
    '''

    ret = {'name': name,
           'changes': {},
           'result': None,
           'comment': ''}

    current_apppools = __salt__['win_iis.list_apppools']()

    if name not in current_apppools:
        ret['comment'] = 'Application pool has already been removed: {0}'.format(name)
        ret['result'] = True
    elif __opts__['test']:
        ret['comment'] = 'Application pool will be removed: {0}'.format(name)
        ret['changes'] = {'old': name,
                          'new': None}
    else:
        ret['comment'] = 'Removed application pool: {0}'.format(name)
        ret['changes'] = {'old': name,
                          'new': None}
        ret['result'] = __salt__['win_iis.remove_apppool'](name)
    return ret