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Complete this python program:
def flt_from_query(query, base_flt=None):
assistant
#Here is the Python program you requested.

    """Return a tuple (`flt`, `archive`, `sortby`, `unused`, `skip`,
    `limit`):
    - a filter based on the query
    - a boolean (`True` iff the filter should be applied to the
    archive collection)
    - a list of [`key`, `order`] to sort results
    - a list of the unused elements of the query (errors)
    - an integer for the number of results to skip
    - an integer for the maximum number of results to return
    """
    unused = []
    sortby = []
    archive = False
    skip = 0
    limit = None
    flt = (get_init_flt() if (base_flt is None) else base_flt)
    def add_unused(neg, param, value):
        'Add    to    the    `unused`    list    a    string    representing    (neg,    param,\n                                value).\n\n                                '
        unused.append(('%s%s' % (('-' if neg else ''), (('%s=%s' % (param, value)) if (value is not None) else param))))
    for (neg, param, value) in query:
        if ((not neg) and (param == 'skip')):
            skip = int(value)
        elif ((not neg) and (param == 'limit')):
            limit = int(value)
        elif (param == 'archives'):
            archive = (not neg)
        elif (param == 'id'):
            flt = db.nmap.flt_and(flt, db.nmap.searchobjectid(value.replace('-', ',').split(','), neg=neg))
        elif (param == 'host'):
            flt = db.nmap.flt_and(flt, db.nmap.searchhost(value, neg=neg))
        elif (param == 'net'):
            flt = db.nmap.flt_and(flt, db.nmap.searchnet(value, neg=neg))
        elif (param == 'range'):
            flt = db.nmap.flt_and(flt, db.nmap.searchrange(neg=neg, *value.replace('-', ',').split(',', 1)))
        elif (param == 'countports'):
            vals = [int(val) for val in value.replace('-', ',').split(',', 1)]
            if (len(vals) == 1):
                flt = db.nmap.flt_and(flt, db.nmap.searchcountopenports(minn=vals[0], maxn=vals[0], neg=neg))
            else:
                flt = db.nmap.flt_and(flt, db.nmap.searchcountopenports(minn=vals[0], maxn=vals[1], neg=neg))
        elif (param == 'hostname'):
            flt = db.nmap.flt_and(flt, db.nmap.searchhostname(utils.str2regexp(value), neg=neg))
        elif (param == 'domain'):
            flt = db.nmap.flt_and(flt, db.nmap.searchdomain(utils.str2regexp(value), neg=neg))
        elif (param == 'category'):
            flt = db.nmap.flt_and(flt, db.nmap.searchcategory(utils.str2regexp(value), neg=neg))
        elif (param ==...