Returns the documentation specific to an HTTP interface

def documentation(self, add_to=None, version=None, prefix="", base_url="", url=""):
        """Returns the documentation specific to an HTTP interface"""
        doc = OrderedDict() if add_to is None else add_to

        usage = self.interface.spec.__doc__
        if usage:
            doc['usage'] = usage

        for example in self.examples:
            example_text = "{0}{1}{2}{3}".format(prefix, base_url, '/v{0}'.format(version) if version else '', url)
            if isinstance(example, str):
                example_text += "?{0}".format(example)
            doc_examples = doc.setdefault('examples', [])
            if not example_text in doc_examples:
                doc_examples.append(example_text)

        doc = super().documentation(doc)

        if getattr(self, 'output_doc', ''):
            doc['outputs']['type'] = self.output_doc

        return doc