1. Why do I get True whenever i tuple the
isinstance(f, (Bar, Foo))
(and why don't the print's run)
The docs say that you can feed it a tuple and that the results are OR'd
----
The form using a tuple, isinstance(x, (A, B, ...)), is a shortcut for
isinstance(x, A) or isinstance(x, B) or ... (etc.).
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which implies that the metaclasses are called for each class?
class MyzMeta(type):
def __instancecheck__(cls, other):
print('MyzzzzzzMeta', other)
return 0
class MyMeta(MyzMeta, object):
def __instancecheck__(cls, other):
print('MyMeta')
print(cls, other)
return 0
class Foo(list):
__metaclass__ = MyzMeta
pass
class Miaow(object):
pass
class Bar(Foo, Miaow):
__metaclass__ = MyMeta
pass
f = Foo()
b = Bar()
print(isinstance(f, (Bar, Foo)))
raise SystemExit
if isinstance(f, (Bar, Foo)):
print('success')
--
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