====== Podstawy przetwarzania tekstu ======
  * https://colab.research.google.com/drive/1ZGpZ3wIX4kMwmgSeDyVhMjaN6vmklo4B?usp=sharing
  * https://colab.research.google.com/drive/1IfDN6yyqSy-z1mucTf87upL_2DeONxR8?usp=sharing