langchain/tools/openapi/utils/api_models.py/APIOperation/_format_nested_properties
class APIOperation:    def _format_nested_properties(
        self, properties: List[APIRequestBodyProperty], indent: int = 2
    ) -> str:
        """Format nested properties."""
        formatted_props = []

        for prop in properties:
            prop_name = prop.name
            prop_type = self.ts_type_from_python(prop.type)
            prop_required = "" if prop.required else "?"
            prop_desc = f"/* {prop.description} */" if prop.description else ""

            if prop.properties:
                nested_props = self._format_nested_properties(
                    prop.properties, indent + 2
                )
                prop_type = f"{{\n{nested_props}\n{' ' * indent}}}"

            formatted_props.append(
                f"{prop_desc}\n{' ' * indent}{prop_name}{prop_required}: {prop_type},"
            )

        return "\n".join(formatted_props)