Is it possible to throw an exception from outside into a generator? What mechanisms are available for this?

Yes, in Python, you can throw an exception into a generator from outside using the throw() method. This method allows you to pass an exception to the point where the generator is currently paused and handle it inside the generator.

Example:

def gen():
    try:
        yield 1
        yield 2
    except ValueError:
        yield 'ValueError handled'

g = gen()
print(next(g))        # Outputs 1
print(g.throw(ValueError))  # Throws an exception into the generator

As a result, the generator will catch the ValueError and can handle it, for example, by returning a special value.

There is also a close() method, which inside the generator raises GeneratorExit, and can be used for proper termination of the generator.