Check time_signature property of MeasurewiseQSchema

[nivlekp]

If we set only a single time signature in MeasurewiseQSchema using the keyword time_signature, then the time_signature would display properly.

>>> q_schema = abjadext.nauert.MeasurewiseQSchema(
...     time_signature=abjad.TimeSignature((3, 4))
... )
>>> q_schema.time_signature
TimeSignature((3, 4))

However, if we are using the non-sequential time-step setting via a dictionary, then it would only return the default time signature (4, 4).

>>> a = {"time_signature": abjad.TimeSignature((7, 32))}
>>> b = {"time_signature": abjad.TimeSignature((3, 4))}
>>> c = {"time_signature": abjad.TimeSignature((5, 8))}

>>> settings = {
...     2: a,
...     4: b,
...     6: c,
... }

>>> q_schema = abjadext.nauert.MeasurewiseQSchema(settings)
>>> q_schema.time_signature
TimeSignature((4, 4))

Maybe this behavior makes sense, maybe not.