code: func validRoleType(roleType string) bool {
  	switch roleType {
  	case credentials.ApplicationRoleType:
  		return true
  	case credentials.ExecutionRoleType:
  		return true
  	default:
  		return false
  	}
  }
docs: // validRoleType returns false if the RoleType in the acs refresh payload is not
  // one of the expected types. TaskApplication, TaskExecution