Parse a chord line into a `ChordLineData` object.

def _parse_chord_line(line):
    ''' Parse a chord line into a `ChordLineData` object. '''
    chords = [
        TabChord(position=position, chord=chord)
        for chord, position in Chord.extract_chordpos(line)
    ]
    return ChordLineData(chords=chords)