Lightweight running of notebooks without Papermill
_tmp_nb = _gen_nb()
assert '3157' not in _tmp_nb.read_text() #value does not exist before execution
_results = str(nbrun(_tmp_nb))
assert '3157' in _results # value exists after execution
assert '98343 + 2' in _results and '98345' not in _results # cells with flags do not get executed
_tmp_nb = _gen_nb()
assert '3157' not in _tmp_nb.read_text() # doesn't exist b/c notebook hasn't been run
nbupdate(_tmp_nb)
assert '3157' in _tmp_nb.read_text() # exists now b/c notebook has been run
_test_nb = _gen_nb()
assert not '3157' in _test_nb.read_text()
parallel_nbupdate(_test_nb)
assert '3157' in _test_nb.read_text()