Since 3.7 `successful` raises a `ValueError` as explained in the next text block from the documentation:
_Changed in version 3.7: If the result is not ready, ValueError is raised instead of AssertionError._
No issue associated with this PR.
Should be backported in 3.7 and 3.8.
(cherry picked from commit
dc0284ee8f7a270b6005467f26d8e5773d76e959)
Co-authored-by: Antoine <43954001+awecx@users.noreply.github.com>
Automerge-Triggered-By: @pitrou
.. method:: successful()
Return whether the call completed without raising an exception. Will
- raise :exc:`AssertionError` if the result is not ready.
+ raise :exc:`ValueError` if the result is not ready.
The following example demonstrates the use of a pool::