Missing runtime dependency: typing-extensions required but not declared

[j-c-c]

In a clean environment, pip install confuse==2.2.0 installs successfully but import confuse fails with ModuleNotFoundError: typing_extensions because the package imports typing_extensions.Self without declaring a typing-extensions runtime dependency.

# Create clean environment
conda create -n confuse_install python=3.11 -y
conda activate confuse_install

# Install confuse
pip install confuse

# Show installed packages
pip freeze

Output:

confuse==2.2.0
PyYAML==6.0.3

# Try importing
python -c "import confuse"

Traceback:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File ".../site-packages/confuse/__init__.py", line 3, in <module>
    from .core import *
  File ".../site-packages/confuse/core.py", line 37, in <module>
    from typing_extensions import Self
ModuleNotFoundError: No module named 'typing_extensions'