This tutorial takes for granted that you have a working Python environment with Python2.6 or Python2.7, with pip installed and you have a working browser to look at the web application you are developing.
Você tem o Python 3.5 - este pode ser o culpado. Existem várias diferenças que podem causar scripts / programas em python destinados a falhas na versão anterior.
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Guido van Rossum (the original creator of the Python language) decided to clean up Python 2.x properly, with less regard for backwards compatibility than is the case for new releases in the 2.x range. The most drastic improvement is the better Unicode support (with all text strings being Unicode by default) as well as saner bytes/Unicode separation.
Besides, several aspects of the core language (such as print and exec being statements, integers using floor division) have been adjusted to be easier for newcomers to learn and to be more consistent with the rest of the language, and old cruft has been removed (for example, all classes are now new-style, "range()" returns a memory efficient iterable, not a list as in 2.x).