Update README.md

Author: huhuhang

README.md

@@ -12,9 +12,9 @@ Python is a versatile, high-level programming language. This Skill Tree offers a
 
 |   Index | Name                                                                                | Difficulty   | Repo                                                                 | Practice                                                             |
 |---------|-------------------------------------------------------------------------------------|--------------|----------------------------------------------------------------------|----------------------------------------------------------------------|
-|       1 | [Quick Start with Python](https://labex.io/courses/quick-start-with-python)         | ★☆☆          | [🔗 Repo](https://github.com/labex-labs/quick-start-with-python)     | [🚀 Start Lab](https://labex.io/courses/quick-start-with-python)     |
-|       2 | [The Advanced Python Mastery](https://labex.io/courses/the-advanced-python-mastery) | ★★★          | [🔗 Repo](https://github.com/labex-labs/the-advanced-python-mastery) | [🚀 Start Lab](https://labex.io/courses/the-advanced-python-mastery) |
-|       3 | [Python Practice Challenges](https://labex.io/courses/python-practice-challenges)   | ★☆☆          | [🔗 Repo](https://github.com/labex-labs/python-practice-challenges)  | [🚀 Start Lab](https://labex.io/courses/python-practice-challenges)  |
+|       1 | [Quick Start with Python](https://labex.io/courses/quick-start-with-python)         | Beginner     | [🔗 Repo](https://github.com/labex-labs/quick-start-with-python)     | [🚀 Start Lab](https://labex.io/courses/quick-start-with-python)     |
+|       2 | [The Advanced Python Mastery](https://labex.io/courses/the-advanced-python-mastery) | Advanced     | [🔗 Repo](https://github.com/labex-labs/the-advanced-python-mastery) | [🚀 Start Lab](https://labex.io/courses/the-advanced-python-mastery) |
+|       3 | [Python Practice Challenges](https://labex.io/courses/python-practice-challenges)   | Beginner     | [🔗 Repo](https://github.com/labex-labs/python-practice-challenges)  | [🚀 Start Lab](https://labex.io/courses/python-practice-challenges)  |
 
 ## More