def __init__(self, spec, data=None, opt=None):
        """Initialize the visualization object."""
        spec = spec
        self.opt = opt or {}
        self.spec = self._prepare_spec(spec, data)
def __init__ ( self , spec , data = None , opt = None ) : spec = spec self . opt = opt or { } self . spec = self . _prepare_spec ( spec , data )
Initialize the visualization object.