human
Complete the below
def _clean_dir(root, keep, exclude_pat):

    ''''Clean out all of the files and directories in a directory (root) while
    preserving the files in a list (keep) and part of exclude_pat'
    '''
assistant
#Here is the Python code you requested.
    removed = set()
    real_keep = set()
    real_keep.add(root)
    if isinstance(keep, list):
        for fn_ in keep:
            if (not os.path.isabs(fn_)):
                continue
            real_keep.add(fn_)
            while True:
                fn_ = os.path.dirname(fn_)
                real_keep.add(fn_)
                if (fn_ in ['/', ''.join([os.path.splitdrive(fn_)[0], '\\\\'])]):
                    break
    def _delete_not_kept(nfn):
        if (nfn not in real_keep):
            if (not salt.utils.check_include_exclude(os.path.relpath(nfn, root), None, exclude_pat)):
                return
            removed.add(nfn)
            if (not __opts__['test']):
                try:
                    os.remove(nfn)
                except OSError:
                    __salt__['file.remove'](nfn)
    for (roots, dirs, files) in os.walk(root):
        for name in itertools.chain(dirs, files):
            _delete_not_kept(os.path.join(roots, name))
    return list(removed)