In general multiprocessing.Pool can interact quite badly with other, seemingly
unrelated, parts of a codebase due to Pool's reliance on fork. This method
cleans up all pools which are known to belong to Keras (and thus can be safely
terminated).
Args
grace_period
Time (in seconds) to wait for process cleanup to propagate.
use_sigkill
Boolean of whether or not to perform a cleanup pass using
SIGKILL.
Returns
A list of human readable strings describing all issues encountered. It is up
to the caller to decide whether to treat this as an error condition.