Custom serializer field to convert human readable date to timestamp

timestamp_field.py

class TimeStampField(serializers.Field):
    """
        A custom serializer field to convert human readable date (2019-04-01) to timestamp(1554094095)
    """
    def to_representation(self, value):
        """
        Convert timestamp to human readable time,
        this function is called when api called to serialize data.
        :param value: timestamp data
        :return: 'YY-mm-dd' (i.e 2019-04-01)
        """
        return datetime.datetime.fromtimestamp(value).date().isoformat()

    def to_internal_value(self, data):
        """
        convert human readable date to timestamp. this function is called when is_valid() method called.
        :param data: Human readable date (2019-04-01)
        :return: timestamp (1554094095)
        """
        date_obj = datetime.datetime.strptime(data, '%Y-%m-%d').date()  # string to date object
        timestamp = time.mktime(date_obj.timetuple())  # date object to timestamp
        return timestamp