    def test_level_as_none(self):
        body = [ast.ImportFrom(module='time',
                               names=[ast.alias(name='sleep')],
                               level=None,
                               lineno=0, col_offset=0)]
        mod = ast.Module(body)
        code = compile(mod, 'test', 'exec')
        ns = {}
        exec(code, ns)
        self.assertIn('sleep', ns)
The software reads data past the end, or before the beginning, of the intended buffer.