fix: make mypy pass on rendered template (pytest via test group, narrow anndata layer value)

Author: Zethson

{{cookiecutter.project_name}}/.pre-commit-config.yaml

@@ -27,7 +27,7 @@ repos:
     hooks:
       - id: mypy
         name: mypy
-        entry: uv run mypy src tests
+        entry: uv run --group test mypy src tests
         language: system
         types: [python]
         files: ^(src|tests)/

{{cookiecutter.project_name}}/src/{{cookiecutter.package_name}}/pp/basic.py

@@ -71,7 +71,7 @@ def elaborate_example(
             msg = f"Item {item} matrix is not a NumPy array but of type {matrix.__class__}."
             raise ValueError(msg)
 
-        result.append(transform(matrix.flatten()))
+        result.append(transform(matrix.flatten()))  # type: ignore[attr-defined]
 
         if len(result) >= max_items:
             break