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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_nbt(self,x,z):
 """ Return a NBT specified by the chunk coordinates x,z. Raise InconceivedChunk if the NBT file is not yet generated. To get a Chunk object, use get_chunk. """

        rx,cx = divmod(x,32)
        rz,cz = divmod(z,32)
        if (rx,rz) not in self.regions and (rx,rz) not in self.regionfiles:
            raise InconceivedChunk("Chunk %s,%s is not present in world" % (x,z))
        nbt = self.get_region(rx,rz).get_nbt(cx,cz)
        assert nbt != None
        return nbt