<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def del_repo(repo, root=None):
    '''
    Delete a repo.

    root
        operate on a different root directory.

    CLI Examples:

    .. code-block:: bash

        salt '*' pkg.del_repo alias
    '''
    repos_cfg = _get_configured_repos(root=root)
    for alias in repos_cfg.sections():
        if alias == repo:
            doc = __zypper__(root=root).xml.call('rr', '--loose-auth', '--loose-query', alias)
            msg = doc.getElementsByTagName('message')
            if doc.getElementsByTagName('progress') and msg:
                return {
                    repo: True,
                    'message': msg[0].childNodes[0].nodeValue,
                }

    raise CommandExecutionError('Repository \'{0}\' not found.'.format(repo))