def METHOD_NAME(self):
    c = Config()
    h1 = c.get_hash()
    # save prev
    prev_log_format = str(c.general.log_format)
    # change
    c.general.log_format = ''
    h2 = c.get_hash()
    self.assertNotEqual(h1, h2)
    # set back
    c.general.log_format = prev_log_format
    h3 = c.get_hash()
    self.assertEqual(h1, h3)