code: function buildMembersArraySchema({ userType, tierRequired }) {
    const keys = {
      MemberId: Joi.number().required(),
      type: userType || Joi.string().required(),
      role: Joi.string().required(),
    }
    if (tierRequired) keys.tier = Joi.string().required()
    return Joi.array().items(Joi.object().keys(keys))
  }
docs: https://developer.opencollective.com/#/api/collectives?id=get-members