code: func merge(envs ...map[string]string) map[string]string {
  	merged := make(map[string]string)
  	for _, env := range envs {
  		for k, v := range env {
  			merged[k] = v
  		}
  	}
  	return merged
  }
docs: // merges the maps together, favoring keys from the right to the left.