Uncommented Classes increase costs

Count one violation each time a class do not have a docstring as first instruction:

bad :

              
                class CustomException
                (Exception)
                :
    def __init__
                (self, msg, code)
                :
        self.msg = msg
        self.code = code

good:

              
                class CustomException
                (Exception)
                :
    """Raise when some custom event did not occur."""
    def __init__
                (self, msg, code)
                :
        self.msg = msg
        self.code = code