code: func FnNot(name string, input interface{}, template interface{}) interface{} {
  	// "Fn::Not": [{condition}]
  
  	// Check the input is an array
  	if arr, ok := input.([]interface{}); ok {
  		if len(arr) != 1 {
  			return nil
  		}
  
  		if value, ok := retrieveCondition(arr[0], template); ok {
  			return !value
  		}
  	}
  
  	return nil
  }
docs: // FnNot resolves the 'Fn::Not' AWS CloudFormation intrinsic function.
  // See: http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-conditions.html#intrinsic-function-reference-conditions-not