* https://py-tutorial-de.readthedocs.io/de/python-3.3/datastructures.html
  * http://www.python-kurs.eu/python3_sequentielle_datentypen.php und http://www.python-kurs.eu/python3_listen.php
  * https://docs.python.org/3.4/tutorial/introduction.html#lists und https://docs.python.org/3.4/tutorial/datastructures.html#more-on-lists