The verification is performed at the application level, in particular, in StringProperty.validate - the corresponding code (which you can find in your SDK sources in the ext / db / init .py file ):
if not self.multiline and value and value.find('\n') != -1:
raise BadValueError('Property %s is not multi-line' % self.name)
, \n , value, . ,
logging.info('value is: %r', value)
put, - ? %r repr , , \n, , .