    def pad_to_multiple_(self, padding_factor):
        """Pad Dictionary size to be a multiple of *padding_factor*."""
        if padding_factor > 1:
            i = 0
            while len(self) % padding_factor != 0:
                symbol = "madeupword{:04d}".format(i)
                self.add_symbol(symbol, n=0)
                i += 1
Pad Dictionary size to be a multiple of *padding_factor*.
fairseq/data/dictionary.py