TypeError with Python annotations

[dt-woods]

When using USEPA's electricityLCI Python package, olca is imported via fedelemflowlist. When running the script through main.py, no errors, but when individual modules are loaded, the following TypeError was encountered. A little research turned up that the annotation style used in ipc.py is supported in Python 3.9+; however, not for Python 3.8 (which is being used here).

A simple fix would be to add a Python version check (e.g., sys.version) and for versions that don't support these annotations, add a future import, from __future__ import annotations, which solved the problem on my end.

from electricitylci.combinator import concat_map_upstream_databases
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "~/python3.8/site-packages/electricitylci/combinator.py", line 4, in <module>
    import electricitylci.generation as gen
  File "~/python3.8/site-packages/electricitylci/generation.py", line 8, in <module>
    from electricitylci.elementaryflows import map_emissions_to_fedelemflows
  File "~/python3.8/site-packages/electricitylci/elementaryflows.py", line 2, in <module>
    import fedelemflowlist
  File "~/python3.8/site-packages/fedelemflowlist/__init__.py", line 10, in <module>
    import fedelemflowlist.jsonld as jsonld
  File "~/python3.8/site-packages/fedelemflowlist/jsonld.py", line 10, in <module>
    import olca
  File "~/python3.8/site-packages/olca/__init__.py", line 4, in <module>
    from .ipc import *
  File "~/python3.8/site-packages/olca/ipc.py", line 146, in <module>
    class Client(object):
  File "~/python3.8/site-packages/olca/ipc.py", line 646, in Client
    def lci_inputs(self, result: schema.SimpleResult) -> list[schema.FlowResult]:
TypeError: 'type' object is not subscriptable

*this is the first of many TypeErrors encountered

More information available on StackOverflow <-- This is not the exact site I found earlier, but close enough.

[Miguel-g-c]

Hi @dt-woods,

We have just included some changes that should solve that. Let us know if this works after updating olca-ipc.py: pip install -U git+https://github.com/GreenDelta/olca-ipc.py.git/@master

[selimyoussry]

Hey @Miguel-g-c , thanks. I believe you missed another one, below the diff I needed to get import olca to work. Thanks for the hard work!

You simply need to replace tuple[...] with Tuple[...] and of course import Tuple from typing at the top.

/work/openlca/olca-ipc.py$ git diff
diff --git a/olca/ipc.py b/olca/ipc.py
index 5d831fc..ae400aa 100644
--- a/olca/ipc.py
+++ b/olca/ipc.py
@@ -7,7 +7,7 @@ import olca.upstream_tree as utree

 from dataclasses import dataclass

-from typing import Any, Iterator, List, Optional, Type, TypeVar, Union
+from typing import Any, Iterator, List, Optional, Tuple, Type, TypeVar, Union

 E = TypeVar('E', bound=schema.RootEntity)
 ModelType = Union[Type[E], str]
@@ -1003,7 +1003,7 @@ class Client(object):
             return None
         return utree.UpstreamTree.from_json(raw)

-    def __post(self, method: str, params) -> tuple[Any, Optional[str]]:
+    def __post(self, method: str, params) -> Tuple[Any, Optional[str]]:
         """
         Performs a request with the given parameters.

[Miguel-g-c]

Hey @selimyoussry, thanks for pointing that out! I've just created a PR which should be merged soon 😁