Error message has unreplaced placeholders

[michael-o]

What went wrong?

Error message contains {0}

How do we reproduce?

$ python3
Python 3.7.7 (default, Mar 19 2020, 21:26:00)
[Clang 9.0.1 (git@github.com:llvm/llvm-project.git c1a0a213378a458fbea1a5c77b31 on freebsd12
>>> context = gssapi.SecurityContext(name=name, usage="initiate", creds=cred)
>>> context.initiator_name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/gssapi/_utils.py", line 64, in inquire_property
    raise AttributeError(msg)
AttributeError: Cannot read {0} from a security context whose establishment has not yet been started.

The error comes from

python-gssapi/gssapi/_utils.py

Lines 62 to 63 in 477b9a6

	msg = ("Cannot read {0} from a security context whose "
	"establishment has not yet been started.")

.

What has to be passed here?

Component versions (python-gssapi, Kerberos, OS / distro, etc.)

Installed via https://www.freshports.org/security/py-gssapi.