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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 replace_all_tokens(self, token):
 """ For all the characters in the screen. Set the token to the given `token`. """

        b = self.data_buffer

        for y, row in b.items():
            for x, char in row.items():
                b[y][x] = _CHAR_CACHE[char.char, token]