Python is a general-purpose programming language. This means that it can be used for anything and everything you would ever want to do with computer languages. Can you therefore conclude that once you have learned Python, you will never need to learn another language?

The answer is that it depends on what you need to do with computer programming. While Python can be used for anything, it is not the most suitable language for everything. For instance, most game programmers use C++ or C# to create their programs, because these languages produce very fast executables, and speed is of utmost importance for games. People who create complex statistical models have their own computer languages too. Sometimes you need to write programs that interact with other programs which require the use of a specific language. And for some problems languages with a different philosophy to writing programs are better suitable.

All in all, while Python basically has no limitations as a programming language, for specific problems specific other languages might be better suitable. Still, for many people Python suffices to do everything they need to do for their studies and job. Moreover, Python is a great language to learn programming with, and once you understand and can use Python, you have a very strong basis to learn any other programming language. That is why I believe it is the language of choice to teach programming to beginners.