code: func (c *Client) FormationBatchUpdate(appIdentity string, updates []FormationBatchUpdateOpts, message string) ([]Formation, error) {
  	params := struct {
  		Updates []FormationBatchUpdateOpts `json:"updates"`
  	}{
  		Updates: updates,
  	}
  	rh := RequestHeaders{CommitMessage: message}
  	var formationsRes []Formation
  	return formationsRes, c.PatchWithHeaders(&formationsRes, "/apps/"+appIdentity+"/formation", params, rh.Headers())
  }
docs: // Batch update process types
  //
  // appIdentity is the unique identifier of the Formation's App. updates is the
  // Array with formation updates. Each element must have "process", the id or
  // name of the process type to be updated, and can optionally update its
  // "quantity" or "size".