code: def valid(self, value, level=[]):
  		
  
  		# Reset validation failures
  		self.validation_failures = []
  
  		# If the value is None and it's optional, we're good
  		if value is None and self._optional:
  			return True
  
  		# Go through each of the nodes
  		for i in range(len(self._nodes)):
  
  			# If it's valid
  			if self._nodes[i].valid(value):
  
  				# Return OK
  				return True
  
  		# Not valid for anything
  		self.validation_failures.append(('.'.join(level), 'no valid option'))
  		return False
docs: Valid
  
  		Checks if a value is valid based on the instance's values
  
  		Arguments:
  			value {mixed} -- The value to validate
  
  		Returns:
  			bool