def test_popSingle(self):
        ctx = _ExecutionContext()
        a = object()
        ctx.push(a)
        ctx.pop()
        self.assertIs(ctx.current(), None)
test that to_synapse_annotations will coerce a list of mixed types to strings
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_action.py/ExecutionContextTests.test_popSingle--crossover with--dataset/ETHPy150Open Sage-Bionetworks/synapsePythonClient/tests/unit/unit_test_annotations.py/test_mixed_annotations