https://colab.research.google.com/github/lmorillas/Introduccion-Python-3/blob/master/beginner/notebooks/file_io.ipynb
Ejercicio: https://colab.research.google.com/github/lmorillas/Introduccion-Python-3/blob/master/beginner/exercises/file_io_exercise.ipynb
Extra https://colab.research.google.com/drive/1R0TvqwbwIu7pmFfZ6u6RY4NDecENl9SG?usp=sharing