Springer has a selection of 400+ books available free due to COVID-19, including some on programming languages such as Python.
E.g. English language books
https://link.springer.com/search?package=mat-covid19_textbooks&facet-language="En"&facet-content-type="Book"
E.g. English language Python books
https://link.springer.com/search?query=Python&facet-language="En"&facet-content-type="Book"&package=mat-covid19_textbooks