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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 json_qry(dataset, qry_str, params={}):
 """ Takes a json query string and returns the results args: dataset: RdfDataset to query against qry_str: query string params: dictionary of params """

    # if qry_str.startswith("$.bf_itemOf[rdf_type=bf_Print].='print',\n"):
    #     pdb.set_trace()
    if not '$' in qry_str:
        qry_str = ".".join(['$', qry_str.strip()])
    dallor_val = params.get("$", dataset)
    if isinstance(dallor_val, rdflib.URIRef):
        dallor_val = Uri(dallor_val)
    if qry_str.strip() == '$':
        return [dallor_val]
    parsed_qry = parse_json_qry(qry_str)
    qry_parts = parsed_qry['qry_parts']
    post_actions = parsed_qry['params']
    # print(qry_parts)
    rtn_list = UniqueList()
    if params.get('dataset'):
        dataset = params['dataset']
    for or_part in qry_parts:
        if or_part[1] == 0:
            if isinstance(dallor_val, dict):
                result = dallor_val
            else:
                try:
                    result = dataset[dallor_val]
                except KeyError:
                    try:
                        result = dataset[Uri(dallor_val)]
                    except KeyError:
                        try:
                            result = dataset[BlankNode(dallor_val)]
                        except KeyError:
                            continue

            forward = True
            for part in or_part[0][1:]:
                if part == "*":
                    forward = not forward
                else:
                    if forward:
                        result = get_json_qry_item(result, part)
                    else:
                        result = get_reverse_json_qry_item(result,
                                                           part,
                                                           False)
        else:
            result = dataset
            parts = or_part[0].copy()
            parts.reverse()
            forward = False
            for part in parts[1:]:
                if part == "*":
                    forward = not forward
                else:
                    if forward:
                        result = get_json_qry_item(result, part)
                    else:
                        result = get_reverse_json_qry_item(result,
                                                           part,
                                                           False,
                                                           dallor_val)
        rtn_list += result
    for action in post_actions:
        rtn_list = action(rtn_list)
    return rtn_list