def __init__(self, column_class=None, *args, **kwargs):
        if kwargs.get('null'):
            raise ValueError('Primary keys cannot be nullable')
        if column_class:
            self.column_class = column_class
        if 'nextval' not in kwargs:
            kwargs['nextval'] = ''
        super(PrimaryKeyField, self).__init__(*args, **kwargs)
dataset/ETHPy150Open kuri65536/python-for-android/sl4atools/fullscreenwrapper2/examples/calcount2_example/peewee.py/PrimaryKeyField.__init__/original