def iterkeys(self):
        self._lookup()
        for key in self._toc.keys():
            yield key
Test if calculate throws an error as expected.
dataset/ETHPy150Open babble/babble/include/jython/Lib/mailbox.py/_singlefileMailbox.iterkeys--crossover with--dataset/ETHPy150Open T-002/pycast/pycast/tests/errormeasuretest.py/BaseErrorMeasureTest.initialize_test