"my brain hurts" or is isinstance broken?

[Robert Kuzelj]

hi,

after playing around with all this metastuff it seems
that isinstance is broken (but after all it could also be, 
that my brain finally broke down).

here some script that checks for the instancetype of various
objects defined within that script.

>>>typestest.py
import types
import string

class metatype(type): pass

class A1: pass
class B1(object): pass
class C1: __metaclass__ = metatype

values = [  [A1, A1()],
            [B1, B1()],
            [C1, C1()]]

def getInstanceInfos(row):
    return [row[0].__name__,
            str(isinstance(row[0], types.InstanceType)),
            str(isinstance(row[0], types.ClassType)), 
            str(isinstance(row[0], types.TypeType)),
            str(isinstance(row[1], types.InstanceType)),
            str(isinstance(row[1], types.ClassType)),
            str(isinstance(row[1], types.TypeType))]

print 
print "INSTANCEINFOS"
print "  name | inst | class | type  | inst  | class | type  "
print "-----------------------------------------------------"
for row in values:
    print "  " + string.join(getInstanceInfos(row), "   |   ")
>>>typestest.py #end

>>>output
INSTANCEINFOS
  name | inst | class | type  | inst  | class | type
-----------------------------------------------------
  A1   |   0   |   1   |   0   |   1   |   0   |   0
  B1   |   0   |   0   |   1   |   0   |   0   |   0
  C1   |   0   |   0   |   1   |   0   |   0   |   0
>>>output

my question is why are the B1() and C1() not types.InstanceType?
and if this is not a bug - of what type are B1() and C1()?

ciao robertj