lecture 3 - https://colab.research.google.com/drive/1FYmo7tx2cXPLtliAAcd6tGM7ZvuGv_Vi?usp=sharing
lecture 4 - https://colab.research.google.com/drive/1gG2JZqHPlRzLKs_JQ9JIRqxp-6eWjRqK?usp=sharing
lecture 5 - https://colab.research.google.com/drive/1HIrzt1NFxBSRnRJ7opA-4ckZz8NIg2PA?usp=sharing
lecture 7 - https://colab.research.google.com/drive/128Q95GoXDVRb_Cijj_CLrM1yfDyvm1RJ?usp=sharing
lecture 8 - https://colab.research.google.com/drive/1XV-THWHudy5lSk4hsKUSSPYnBSIhHXVc?usp=sharing