code: func (s *FakeAWSServices) WithAz(az string) *FakeAWSServices {
  	if s.selfInstance.Placement == nil {
  		s.selfInstance.Placement = &ec2.Placement{}
  	}
  	s.selfInstance.Placement.AvailabilityZone = aws.String(az)
  	return s
  }
docs: // WithAz sets the ec2 placement availability zone