PYTHON

pytube.exceptions.RegexMatchError: get_throttling_function_name: could not find match for multiple

Becuase youtube changed something on its end, and now you have to change pytube's ciper.py's function_patterns to the following
line: 272 ~ 273
r'a.[a-zA-Z]s*&&s*([a-z]s*=s*a.get("n"))s*&&s*'
r'([a-z]s*=s*([a-zA-Z0-9$]{2,3})([d+])?([a-z])'

line: 288

nfunc=re.escape(function_match.group(1))),

RegexMatchError: get_throttling_function_name: could not find match for multiple pytube

try upgrading pytube like this:
pip install pytube --upgrade