def METHOD_NAME():
    cell = create_grade_cell("", "code", "foo", 2, 0)
    del cell.metadata.nbgrader["solution"]
    del cell.metadata.nbgrader["locked"]
    MetadataValidatorV1().upgrade_cell_metadata(cell)
    assert not cell.metadata.nbgrader["solution"]
    assert not cell.metadata.nbgrader["locked"]
    cell = create_solution_cell("", "code", "foo", 0)
    del cell.metadata.nbgrader["grade"]
    del cell.metadata.nbgrader["locked"]
    MetadataValidatorV1().upgrade_cell_metadata(cell)
    assert not cell.metadata.nbgrader["grade"]
    assert not cell.metadata.nbgrader["locked"]