def METHOD_NAME(
    project: Project,
    target_type: ActionTargetType,
    target_identifier: str | None,
    fallthrough_choice: FallthroughChoiceType | None,
) -> str:
    target_str = target_identifier if target_identifier is not None else ""
    fallthrough = fallthrough_choice.value if fallthrough_choice is not None else ""
    return f"mail:p:{project.id}:{target_type.value}:{target_str}:{fallthrough}"