Python 2.7 installing opencv via pip (virtual environment)
Solution 1:
Python 2.7 is not supported anymore in opencv-python-4.3.0.38. Support was dropped in 4.3.0.36; see this issue.
The workaround I found was to install opencv-python version 4.2.0.32 (which is the latest supported for Python 2.7, see this for all releases) like this:
pip2 install opencv-python==4.2.0.32