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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 _highlight_digraph(self, cli, new_screen):
 """ When we are in Vi digraph mode, put a question mark underneath the cursor. """

        digraph_char = self._get_digraph_char(cli)
        if digraph_char:
            cpos = new_screen.cursor_position
            new_screen.data_buffer[cpos.y][cpos.x] = \
                _CHAR_CACHE[digraph_char, Token.Digraph]