New in version 2.0.
Integer-equivalent number to integer:
abjad> from abjad.tools import mathtools
abjad> mathtools.integer_equivalent_number_to_integer(17.0)
17
Return noninteger-equivalent number unchanged:
abjad> mathtools.integer_equivalent_number_to_integer(17.5)
17.5
Raise type error on nonnumber input.
Return number.