def __setattr__(self, attr, val):
        if attr != '__dict__' and hasattr(self, attr):
            raise AttributeError('Attribute "%s" already set' % attr)
        super(BunchConst, self).__setattr__(attr, val)
dataset/ETHPy150Open mne-tools/mne-python/mne/io/constants.py/BunchConst.__setattr__/original