• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: both debian and macOS
• Poetry version: 1.1.2

Issue

If I run the following poetry add 'camelot-py[cv]' then I correctly get the following in pyproject.toml

[tool.poetry.dependencies]
python = "^3.8"
camelot-py = {extras = ["cv"], version = "^0.8.2"}

But opencv-python is not installed as stated in extras_require in setup.py. If I use pip install 'camelot-py[cv]' then it works as expected