@classmethod
def convert_to_timestamps(cls, tracks_row_strings):
    """Accepts tracks durations in hh:mm:ss format; one per row"""
    lines = cls.parse_tracks_hhmmss(tracks_row_strings)
    i = 1
    timestamps = ['0:00']
    while i < len(lines):
        timestamps.append(cls.add(timestamps[i - 1], lines[i - 1][-1]))
        i += 1
    return timestamps
