Function pylong_from_digits 

pub(crate) fn pylong_from_digits<'py, I: ExactSizeIterator<Item = u32>>(
    py: Python<'py>,
    negative: bool,
    digits: I,
) -> Bound<'py, PyInt>

Available on Py_3_15, or Py_3_14 and non-Py_LIMITED_API only.