How to use the numerapi.utils.replace function in numerapi

def test_replace():
    d = None
    assert utils.replace(d, "a", float) is None
    # empty dict
    d = {}
    assert not utils.replace(d, "a", float)
    # normal case
    d = {"a": "1"}
    utils.replace(d, "a", float)
    assert d["a"] == 1.0

roundNumber
                tournamentId
                soc
                staker
                status
                txHash
                value
              }
            }
          }
        """
        data = self.raw_query(query, authorization=True)['data']
        stakes = data['user']['stakeTxs']
        # convert strings to python objects
        for s in stakes:
            utils.replace(s, "insertedAt", utils.parse_datetime_string)
            utils.replace(s, "soc", utils.parse_float_string)
            utils.replace(s, "confidence", utils.parse_float_string)
            utils.replace(s, "value", utils.parse_float_string)
        return stakes

name
                public_id
                scopes
              }
              v2Stake {
                status
                txHash
              }
            }
          }
        """
        data = self.raw_query(query, authorization=True)['data']['user']
        # convert strings to python objects
        utils.replace(data, "insertedAt", utils.parse_datetime_string)
        utils.replace(data, "availableUsd", utils.parse_float_string)
        utils.replace(data, "availableNmr", utils.parse_float_string)
        return data

}
        '''
        arguments = {'number': round_num, 'tournament': tournament}
        result = self.raw_query(query, arguments)['data']['rounds'][0]
        if result is None:
            return None
        stakes = result['leaderboard']
        # filter those with actual stakes
        stakes = [item for item in stakes if item["stake"] is not None]
        # convert strings to python objects
        for s in stakes:
            utils.replace(s["stake"], "insertedAt",
                          utils.parse_datetime_string)
            utils.replace(s["stake"], "confidence", utils.parse_float_string)
            utils.replace(s["stake"], "soc", utils.parse_float_string)
            utils.replace(s["stake"], "value", utils.parse_float_string)
        return stakes

'''
        arguments = {'tournament': tournament, 'username': username}
        data = self.raw_query(query, arguments)['data']['userActivities']
        # filter rounds with no activity
        data = [item for item in data
                if item['submission']['date'] is not None]
        for item in data:
            # remove stakes with all values set to None
            if item['stake']['date'] is None:
                del item['stake']
            # parse
            else:
                utils.replace(item['stake'], "date",
                              utils.parse_datetime_string)
                for col in ['confidence', 'value', 'nmrEarned', 'usdEarned']:
                    utils.replace(item['stake'], col, utils.parse_float_string)
        # parse
        for item in data:
            utils.replace(item['submission'], "date",
                          utils.parse_datetime_string)
        return data

'''
        arguments = {'number': round_num, 'tournament': tournament}
        result = self.raw_query(query, arguments)['data']['rounds']

        if len(result) == 0:
            msg = "no entries for round number {} & tournament ".format(
                round_num, tournament)
            self.logger.warning(msg)
            raise ValueError

        leaderboard = result[0]['leaderboard']
        # parse to correct data types
        for item in leaderboard:
            for p in ["paymentGeneral", "paymentStaking"]:
                utils.replace(item[p], "nmrAmount", utils.parse_float_string)
                utils.replace(item[p], "usdAmount", utils.parse_float_string)
            utils.replace(item['stakeResolution'], "paid",
                          utils.parse_float_string)
            utils.replace(item['return'], "nmrAmount",
                          utils.parse_float_string)
        return leaderboard

query($roundNumber: Int!) {
            v2RoundDetails(roundNumber: $roundNumber) {
              userPerformances {
                date
                correlation
                username
              }
            }
          }
        """
        arguments = {'roundNumber': round_num}
        data = self.raw_query(query, arguments)['data']['v2RoundDetails']
        performances = data['userPerformances']
        # convert strings to python objects
        for perf in performances:
            utils.replace(perf, "date", utils.parse_datetime_string)
        return performances