def form_fields(self) -> MutableMapping[str, HtmlElement]:
        """Return fields of default form.

        Fill some fields with reasonable values.
        """
        fields = dict(self.form.fields)
        self.process_form_fields(fields)
        for elem in self.form.inputs:
            if (
                elem.tag == "select"
                and elem.name in fields
                and fields[elem.name] is None
                and elem.value_options
            ):
                fields[elem.name] = elem.value_options[0]
            elif (getattr(elem, "type", None) == "radio") and fields[elem.name] is None:
                fields[elem.name] = elem.get("value")
        for name in self.build_fields_to_remove(fields, self.form.inputs):
            del fields[name]
        return fields
Return fields of default form.

        Fill some fields with reasonable values.
        
grab/document.py