New in version 2.6.
True when expr is a sequence of Abjad chords:
abjad> chords = [Chord("<c' e' g'>4"), Chord("<c' f' a'>4")]
abjad> chordtools.all_are_chords(chords)
True
True when expr is an empty sequence:
abjad> chordtools.all_are_chords([])
True
Otherwise false:
abjad> chordtools.all_are_chords('foo')
False
Return boolean.
Function wraps componenttools.all_are_components().