Generated by `pyupgrade --py3-plus --keep-percent-format` on all our
Python code except `zthumbor` and `zulip-ec2-configure-interfaces`,
followed by manual indentation fixes.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
This is a preparatory commit for using isort for sorting all of our
imports, merging changes to files where we can easily review the
changes as something we're happy with.
These are also files with relatively little active development, which
means we don't expect much merge conflict risk from these changes.
This adds a model field `invited_as` to PreregistrationUser model class
which will replace `invited_as_admin` in future. Intentions behind adding
this are that we can specify "types" of users for an invited person other
than admin or regular that is, guest user or maybe many others in the
future.