code: func (c *Client) PlanInfo(addonServiceIdentity string, planIdentity string) (*Plan, error) {
  	var plan Plan
  	return &plan, c.Get(&plan, "/addon-services/"+addonServiceIdentity+"/plans/"+planIdentity)
  }
docs: // Info for existing plan.
  //
  // addonServiceIdentity is the unique identifier of the Plan's AddonService.
  // planIdentity is the unique identifier of the Plan.