The functools module imports reduce from _functools, using a guard in case it is not present:

try:
    from _functools import reduce
except ImportError:
    pass


However, the documentation says nothing about reduce being optional, and it is unconditionally included in the module __all__.

If reduce is guaranteed to be implemented in _functools, then the guard is redundant and should be removed. Otherwise, a pure python fallback should be added.

(The docs for reduce include a pure Python equivalent which might be sufficient.)