def test_command(subdevice, num_tests=2):
"""Adjust a command as necessary to get valid arguments.
"""
_LOG.info('command before testing:\n{}'.format(subdevice.cmd))
for i in range(2):
rc = subdevice.command_test()
if rc is None:
_LOG.info('command is valid')
return
_LOG.info('test {} returned {}\n{}'.format(i, rc, subdevice.cmd))
_LOG.error('error preparing command: {}'.format(rc))
_sys.exit(1)
