def _parse_id_and_array_filter(self, list_element_field, filtered_field):
        """Converts the ``list_element_field`` and ``filtered_field`` to an
        element object ID and array filter.

        Example::

            Input:
                list_element_field = "test_dets.detections.1.label"
                filtered_field = "test_dets.detections"

            Output:
                ObjectId("5f2062bf27c024654f5286a0")
                "test_dets.detections.$[element].label"
        """
        el = self
        for field_name in filtered_field.split("."):
            el = el[field_name]

        el_fields = (
            list_element_field[len(filtered_field) :].lstrip(".").split(".")
        )
        idx = int(el_fields.pop(0))

        el = el[idx]
        el_filter = ".".join([filtered_field, "$[element]"] + el_fields)

        return el._id, el_filter
Converts the ``list_element_field`` and ``filtered_field`` to an
        element object ID and array filter.

        Example::

            Input:
                list_element_field = "test_dets.detections.1.label"
                filtered_field = "test_dets.detections"

            Output:
                ObjectId("5f2062bf27c024654f5286a0")
                "test_dets.detections.$[element].label"
        
fiftyone/core/odm/mixins.py