code: def regex(self, regex = None):
  		
  
  		# If regex was not set, this is a getter
  		if regex is None:
  			return self._regex
  
  		# If the type is not a string
  		if self._type != 'string':
  			sys.stderr.write('can not set __regex__ for %s' % self._type)
  			return
  
  		# If it's not a valid string or regex
  		if not isinstance(regex, (basestring, _REGEX_TYPE)):
  			raise ValueError('__regex__')
  
  		# Store the regex
  		self._regex = regex
docs: Regex
  
  		Sets or gets the regular expression used to validate the Node
  
  		Arguments:
  			regex {str} -- A standard regular expression string
  
  		Raises:
  			ValueError
  
  		Returns:
  			None | str