Fix could_be_deleted definition?

1 job for delete-duplicate-membershipfee in 2 minutes and 40 seconds
Status Job ID Name Coverage
  Test
failed #283
unit_tests_debian_10

00:02:40

 
Name Stage Failure
failed
unit_tests_debian_10 Test
coin/members/tests.py::MemberTestCallForMembershipCommand::test_call_email_sent_at_expected_dates
coin/members/tests.py::MemberTestCallForMembershipCommand::test_date_last_call_for_membership_fees_email
/builds/arn/coin/coin/utils.py:90: RemovedInDjango110Warning: render() must be called with a dict, not a Context.
subject = subject_template.render(Context(context))

-- Docs: https://docs.pytest.org/en/latest/warnings.html
======== 1 failed, 51 passed, 18 skipped, 122 warnings in 54.87 seconds ========
Cleaning up file based variables
ERROR: Job failed: exit code 1