Angelos Evripiotis authored Apr 02, 2019 and bst-marge-bot committed Apr 09, 2019

Remove the unintended side-effect of only being able to iterate the
ref_callbacks results once. This would mean that subsequent calls to
clean() were not honoring the required_refs correctly.

Update CasQuota.clean() to call the ref callbacks and iterate over
their results.

When registering ref callbacks; pass the methods, and not the generators
that they return.