code: func copyVPC(in vpc.VPC) vpc.VPC {
  	securityGroups := make([]string, len(in.SecurityGroups))
  	copy(securityGroups, in.SecurityGroups)
  	subnets := make([]string, len(in.Subnets))
  	copy(subnets, in.Subnets)
  
  	return vpc.VPC{
  		SecurityGroups: securityGroups,
  		Subnets:        subnets,
  	}
  }
docs: // copyVPC returns a copy of `in`.