this is copied from sphinx.directives.code.CodeBlock.run

        it has been changed to accept code and language as an arguments instead
        of reading from self

def get_codeblock_node(self, code, language):
        """this is copied from sphinx.directives.code.CodeBlock.run

        it has been changed to accept code and language as an arguments instead
        of reading from self

        """

        # type: () -> List[nodes.Node]
        document = self.state.document
        location = self.state_machine.get_source_and_line(self.lineno)

        linespec = self.options.get('emphasize-lines')
        if linespec:
            try:
                nlines = len(code.split('\n'))
                hl_lines = parselinenos(linespec, nlines)
                if any(i >= nlines for i in hl_lines):
                    log.warning(__('line number spec is out of range(1-%d): %r') %
                                   (nlines, self.options['emphasize-lines']),
                                   location=location)

                hl_lines = [x + 1 for x in hl_lines if x < nlines]
            except ValueError as err:
                return [document.reporter.warning(str(err), line=self.lineno)]
        else:
            hl_lines = None

        if 'dedent' in self.options:
            location = self.state_machine.get_source_and_line(self.lineno)
            lines = code.split('\n')
            lines = dedent_lines(lines, self.options['dedent'], location=location)
            code = '\n'.join(lines)

        literal = nodes.literal_block(code, code)
        literal['language'] = language
        literal['linenos'] = 'linenos' in self.options or \
                             'lineno-start' in self.options
        literal['classes'] += self.options.get('class', [])
        extra_args = literal['highlight_args'] = {}
        if hl_lines is not None:
            extra_args['hl_lines'] = hl_lines
        if 'lineno-start' in self.options:
            extra_args['linenostart'] = self.options['lineno-start']
        set_source_info(self, literal)

        caption = self.options.get('caption')
        if caption:
            try:
                literal = container_wrapper(self, literal, caption)
            except ValueError as exc:
                return [document.reporter.warning(text_type(exc), line=self.lineno)]

        # literal will be note_implicit_target that is linked from caption and numref.
        # when options['name'] is provided, it should be primary ID.
        self.add_name(literal)

        return [literal]