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>
It's theoretically possible to have configured a Zulip server where
the system bots live in the same realm as normal users (and may have
in fact been the default in early Zulip releases? Unclear.). We
should handle these without the migration intended to clean up naming
for the system bot realm crashing.
Fixes#13660.
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.