pi@raspberrypi:~ $ python3
Python 3.7.3 (default, Jan 22 2021, 20:04:44)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> class Exc(BaseException):
...     def __new__(cls, *args, **kwargs):
...         return Exc()
...
>>> def gen():
...   yield
...
>>> gen().throw(Exc)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 1, in gen
  File "<stdin>", line 3, in __new__
  File "<stdin>", line 3, in __new__
  File "<stdin>", line 3, in __new__
  [Previous line repeated 496 more times]
RecursionError: maximum recursion depth exceeded while calling a Python object