Allow to give a save path directly

src/jobflow/core/store.py

@@ -21,9 +21,17 @@
 
     from jobflow.core.schemas import JobStoreDocument
 
-    obj_type = Union[str, Enum, type[MSONable], list[Union[Enum, str, type[MSONable]]]]
-    save_type = Optional[dict[str, obj_type]]
-    load_type = Union[bool, dict[str, Union[bool, obj_type]]]
+    obj_save_type = Union[
+        str,
+        Enum,
+        type[MSONable],
+        list[Union[Enum, str, type[MSONable], list[Union[str, type[MSONable]]]]],
+    ]
+    save_type = Optional[dict[str, obj_save_type]]
+    obj_load_type = Union[
+        str, Enum, type[MSONable], list[Union[Enum, str, type[MSONable]]]
+    ]
+    load_type = Union[bool, dict[str, Union[bool, obj_load_type]]]
 
 
 T = typing.TypeVar("T", bound="JobStore")
@@ -43,6 +51,9 @@ class JobStore(Store):
         Which items to save in additional stores when uploading documents. Given as a
         mapping of ``{store name: store_type}`` where ``store_type`` can be a dictionary
         key (string or enum), an :obj:`.MSONable` class, or a list of keys/classes.
+        If the list of keys/classes itself contains a list, this will be treated
+        as the path to the save key. Can be used if a key is duplicate in the output
+        and only a single occurrence shall be put in the additional store.
     load
         Which items to load from additional stores when querying documents. Given as a
         mapping of ``{store name: store_type}`` where ``store_type`` can be `True``, in
@@ -304,7 +315,10 @@ def update(
                 locations = []
                 for store_name, store_save in save_keys.items():
                     for save_key in store_save:
-                        locations.extend(find_key(doc, save_key, include_end=True))
+                        if isinstance(save_key, list):
+                            locations.append(save_key)
+                        else:
+                            locations.extend(find_key(doc, save_key, include_end=True))
 
                     locations = get_root_locations(locations)
                     objects = [get(doc, list(loc)) for loc in locations]
@@ -726,7 +740,7 @@ def _prepare_load(
 
 def _prepare_save(
     save: bool | save_type,
-) -> dict[str, list[str | type[MSONable]]]:
+) -> dict[str, list[str | type[MSONable] | list[str | type[MSONable]]]]:
     """Standardize save type."""
     from enum import Enum