code: function(userProfileServiceInstance) {
      if (typeof userProfileServiceInstance.lookup !== 'function') {
        throw new Error(sprintf(ERROR_MESSAGES.INVALID_USER_PROFILE_SERVICE, MODULE_NAME, 'Missing function \'lookup\''));
      } else if (typeof userProfileServiceInstance.save !== 'function') {
        throw new Error(sprintf(ERROR_MESSAGES.INVALID_USER_PROFILE_SERVICE, MODULE_NAME, 'Missing function \'save\''));
      }
      return true;
    }
docs: Validates user's provided user profile service instance
  @param  {Object}  userProfileServiceInstance
  @return {boolean} True if the instance is valid
  @throws If the instance is not valid