New in version 1.1.
True when expr is a sequence and all elements in expr are numbers:
abjad> from abjad.tools import sequencetools
abjad> sequencetools.all_are_numbers([1, 2, 3.0, Fraction(13, 8)])
True
True when expr is an empty sequence:
abjad> sequencetools.all_are_numbers([])
True
False otherwise:
abjad> sequencetools.all_are_numbers(17)
False
Return boolean.
Changed in version 2.0: renamed sequencetools.is_numeric() to sequencetools.all_are_numbers().