How to use the prosodic.lib.MaxEnt.DataPoint function in prosodic

if split[3] == "":
                        frequency = 0.0
                    else:
                        frequency = float(split[3])

                else:
                    line = line.strip()
                    split = line.split(delimeter)
                    text = split[0]
                    frequency = float(split[1])
                    scansion = split[2]

                if text not in data:
                    data[text] = []

                datum = DataPoint(text, scansion, None, frequency)
                data[text].append(datum)

        return data

if self.constraints is None:
                    self.constraints = []
                    for constraint in constraint_violations:
                        self.constraints.append(constraint)

                constraint_viol_count = []
                for constraint in self.constraints:
                    constraint_viol_count.append(constraint_violations[constraint] / constraint.weight)

                frequency = 0.0
                for datum in data[line]:
                    if datum.scansion == meter_str:
                        frequency = datum.frequency
                        matched = True

                data_point = DataPoint(line, meter_str, scansion_str, frequency)
                data_point.violations = constraint_viol_count
                parse_list.append(data_point)



            full_parses[line] = parse_list


        return full_parses