New Python Program: To-Do List Manager

建立新的 todo_manager.py 檔案，並先檢視 issue 中對選單、任務操作和錯誤處理的要求。以互動方式執行程式，以驗證新增、完成、檢視和移除任務的功能，包括無效的任務選取。完成的定義是所要求的函式和對使用者友善的提示在 Python 3.x 中運作正常，且這些情境都已完成測試。

Hello Python enthusiasts! Let's enhance our repository with a To-Do List Manager implemented in Python. This beginner-friendly task involves creating a program that allows users to add tasks, mark tasks as completed, view the to-do list, and remove completed tasks. This task will showcase data structures, loops, and conditional statements in Python.

Tasks:

• Implement functions to add tasks, mark tasks as completed, view the to-do list, and remove completed tasks.
• Store tasks in a list or dictionary data structure.
• Provide user-friendly menus and prompts for each operation.
• Handle errors gracefully, such as accessing tasks that don't exist.
• Ensure completed tasks can be removed from the list.

Guidelines:

• Use Python 3.x for the program.
• Implement functions for each operation (add_task, mark_completed, view_tasks, remove_completed, etc.).
• Include comments in your code to explain the logic and functionality.
• Test the program thoroughly, covering various scenarios including adding, completing, and removing tasks.

Example:

Welcome to the To-Do List Manager!

1. Add Task
2. Mark Task as Completed
3. View To-Do List
4. Remove Completed Tasks
5. Exit

Select an option: 1
Enter task: Complete Python project
Task 'Complete Python project' added successfully!

1. Add Task
2. Mark Task as Completed
3. View To-Do List
4. Remove Completed Tasks
5. Exit

Select an option: 3
To-Do List:
1. [ ] Complete Python project

...

How to Contribute:

1. Fork this repository.
2. Create a new Python file for the To-Do List Manager: todo_manager.py.
3. Write the Python program following the specified tasks and guidelines.
4. Test the program thoroughly to ensure it functions correctly.
5. Commit your changes: git commit -m "Add To-Do List Manager program"
6. Push to your branch: git push origin add-todo-manager
7. Open a pull request to this repository.

Your contribution will provide users with a practical tool for managing tasks. Thank you for creating this useful Python program for our repository!