When I run this (2.7.3) I get this output:

```
'Slotted1' object has no attribute 'c'
attribute c added to <class '__main__.Slotted2'>

```

I don't understand the difference in behavior between Slotted1 and Slotted2. Can anyone explain? 

```
from ctypes import *

class BracedStructure(Structure):
    def __init__(self, **args):
        super(BracedStructure,self).__init__(**args) 

class Slotted1(Structure):
    __slots__ = ['a','b']
    _fields_ = [('a',c_int8),('b',c_int8)]  
    def __init__(self, **args):
        super(Slotted1,self).__init__(**args)
    def attemptToAddField(self):
        self.c = '?'
        print 'attribute c added to %s' % self.__class__

class Slotted2(BracedStructure):
    __slots__ = ['a','b']
    _fields_ = [('a',c_int8),('b',c_int8)]  
    def __init__(self, **args):
        super(Slotted2,self).__init__(**args)
    def attemptToAddField(self):
        self.c = '?'
        print 'attribute c added to %s' % self.__class__

if '__main__' == __name__:
    s1 = Slotted1(a=1,b=2)
    try:
        s1.attemptToAddField()
    except AttributeError as e:
        print e

    s2 = Slotted2(a=1,b=2)
    try:
        s2.attemptToAddField()
    except AttributeError as e:
        print e

```