If the following code is called where L is a list, how is L used?
raise A, L
Note that this syntax is only available in Python 2. Python 3 has lib2to3/fixes/fix_raise.py
in its 2-to-3 translation system, which starts with the following docstring, giving you a hint about things the documentation stays silent on (AFAIK):
Fixer for 'raise E, V, T'
raise -> raise
raise E -> raise E
raise E, V -> raise E(V)
raise E, V, T -> raise E(V).with_traceback(T)
raise E, None, T -> raise E.with_traceback(T)
raise (((E, E'), E''), E'''), V -> raise E(V)
raise "foo", V, T -> warns about string exceptions
CAVEATS:
1) "raise E, V" will be incorrectly translated if V is an exception
instance. The correct Python 3 idiom is
raise E from V
but since we can't detect instance-hood by syntax alone and since
any client code would have to be changed as well, we don't automate
this.
What it boils down to is that raise FooException, [1, 2] is equivalent to raise FooException([1, 2]); but you should always use the latter.