How to use the pandocfilters.CodeBlock function in pandocfilters

def plain_output(text: str, pandoc_format: str="markdown",
                 pandoc_extra_args: list=None, pandoc: bool=False) -> list:
    if pandoc:
        return tokenize_block(text, pandoc_format, pandoc_extra_args)
    else:
        return [Div(['', ['output'], []], [CodeBlock(['', [], []], text)])]

def plain_output(text: str, pandoc_extra_args: list=None, pandoc: bool=False) -> list:
    if pandoc:
        return tokenize_block(text, pandoc_extra_args)
    else:
        return [Div(['', ['output'], []], [CodeBlock(['', [], []], text)])]

def image(self):
        'returns documentation in a CodeBlock'
        # CodeBlock value = [(Identity, [classes], [(key, val)]), code]
        if not self.code:
            return pf.CodeBlock(('', [], []), __doc__)
        elif self.code == 'classes':
            classes = wrap(', '.join(sorted(Handler.workers.keys())), 78)
            return pf.CodeBlock(('', [], []), '\n'.join(classes))

        doc = []
        for name in self.code.splitlines():
            name = name.lower()
            worker = self.workers.get(name, None)
            doc.append("Codeblock class: " + name)
            if worker is None:
                doc.append('No worker found for %s' % name)
                continue
            if worker.__doc__:
                doc.append(worker.__doc__)
                doc.append("    runs:")
                doc.append('    > ' + worker.image.__doc__)
            else:
                doc.append('No help available.')

def image(self):
        'returns documentation in a CodeBlock'
        # CodeBlock value = [(Identity, [classes], [(key, val)]), code]
        if not self.code:
            return pf.CodeBlock(('', [], []), __doc__)
        elif self.code == 'classes':
            classes = wrap(', '.join(sorted(Handler.workers.keys())), 78)
            return pf.CodeBlock(('', [], []), '\n'.join(classes))

        doc = []
        for name in self.code.splitlines():
            name = name.lower()
            worker = self.workers.get(name, None)
            doc.append("Codeblock class: " + name)
            if worker is None:
                doc.append('No worker found for %s' % name)
                continue
            if worker.__doc__:
                doc.append(worker.__doc__)
                doc.append("    runs:")
                doc.append('    > ' + worker.image.__doc__)

else:
                    msg = '?? missing %s' % self.outfile
                    self.msg(1, msg)
                    rv.append(pf.Para([pf.Str(msg)]))

            elif output_elm == 'fcb':
                rv.append(self.anon_codeblock())

            elif output_elm == 'ocb':
                attr = ['', self.classes, self.keyvals]
                rv.append(pf.CodeBlock(attr, self.codec[1]))

            elif output_elm == 'stdout':
                if self.stdout:
                    attr = ['', self.classes, self.keyvals]
                    rv.append(pf.CodeBlock(attr, to_str(self.stdout, enc)))
                else:
                    self.msg(1, 'stdout requested, but saw nothing')

            elif output_elm == 'stderr':
                if self.stderr:
                    attr = ['', self.classes, self.keyvals]
                    rv.append(pf.CodeBlock(attr, to_str(self.stderr, enc)))
                else:
                    self.msg(1, 'stderr requested, but saw nothing')

        if not rv:
            return None               # no results; None keeps original FCB
        if len(rv) > 1:
            return rv                 # multiple results
        return rv[0]                  # just 1 block level element

def code_include(key, value, format, meta):
    if key == 'CodeBlock':
        [[ident, classes, namevals], code] = value
        for nameval in namevals:
            if nameval[0] == 'include':
                with open(nameval[1], 'rb') as content_file:
                    content = content_file.read()
                    content.decode('utf-8')
                namevals.remove(nameval)
                return CodeBlock([ident, classes, namevals], content)

for k,v in self.md_opts.items():
                if k not in self.workers:
                    glob_opts.append("    imagine.{}: {}".format(k,v))
                else: # elif k == name:
                    for kk,vv in self.md_opts.get(name, {}).items():
                        klass_opts.append("    imagine.{}.{}: {}".format(k,
                            kk,vv))
            if klass_opts or glob_opts:
                doc.append("\nMetadata options")
                # doc.append("    ---")
                doc.extend(glob_opts + klass_opts)
                # doc.append("    ...")

            doc.append('\n')

        return pf.CodeBlock(('', [], []), '\n'.join(doc))

enc = sys.getdefaultencoding()  # result always unicode
        for output_elm in self.im_out:
            if output_elm == 'img':
                if os.path.isfile(self.outfile):
                    rv.append(pf.Para([self.url()]))
                else:
                    msg = '?? missing %s' % self.outfile
                    self.msg(1, msg)
                    rv.append(pf.Para([pf.Str(msg)]))

            elif output_elm == 'fcb':
                rv.append(self.anon_codeblock())

            elif output_elm == 'ocb':
                attr = ['', self.classes, self.keyvals]
                rv.append(pf.CodeBlock(attr, self.codec[1]))

            elif output_elm == 'stdout':
                if self.stdout:
                    attr = ['', self.classes, self.keyvals]
                    rv.append(pf.CodeBlock(attr, to_str(self.stdout, enc)))
                else:
                    self.msg(1, 'stdout requested, but saw nothing')

            elif output_elm == 'stderr':
                if self.stderr:
                    attr = ['', self.classes, self.keyvals]
                    rv.append(pf.CodeBlock(attr, to_str(self.stderr, enc)))
                else:
                    self.msg(1, 'stderr requested, but saw nothing')

        if not rv:

def anon_codeblock(self):
        'reproduce the original CodeBlock inside an anonymous CodeBlock'
        (id_, klasses, keyvals), code = self.codec
        id_ = '#' + id_ if id_ else id_
        klasses = ' '.join('.%s' % c for c in klasses)
        keyvals = ' '.join('%s="%s"' % (k, v) for k, v in keyvals)
        attr = '{%s}' % ' '.join(a for a in [id_, klasses, keyvals] if a)
        # prefer ```cmd over ```{.cmd}
        attr = attr if attr.find(' ') > -1 else attr[2:-1]
        codeblock = '```%s\n%s\n```' % (attr, code)
        return pf.CodeBlock(['', [], []], codeblock)