I had to reinstall my MacBook. I downloaded python from brew.
When I copy and paste code in the python shell from brew, the text is highlighted and the code not executed.
When I use the stock python from my MacBook there is no problem.
Please check this short video: https://youtu.be/CrTzBpVdcVM
I'm not the only one with this problem, however no solutions had been found yet:
SyntaxError when pasting multiple lines in Python
https://python-forum.io/Thread-How-to-paste-several-lines-of-codes-to-the-Python-console