def __init__(self, data, subject, xfmname, mask=None, **kwargs):
        """Three possible variables: volume, movie, vertex. Enumerated with size:
        volume movie: (t, z, y, x)
        volume image: (z, y, x)
        linear movie: (t, v)
        linear image: (v,)
        """
        if self.__class__ == VolumeData:
            raise TypeError('Cannot directly instantiate VolumeData objects')
        super(VolumeData, self).__init__(data, subject, **kwargs)
        try:
            basestring
        except __HOLE__:
            xfmname = xfmname if isinstance(xfmname, str) else xfmname.decode('utf-8')
        self.xfmname = xfmname

        self._check_size(mask)
        self.masked = _masker(self)
dataset/ETHPy150Open gallantlab/pycortex/cortex/dataset/braindata.py/VolumeData.__init__