ERROR: Could not find a version that satisfies the requirement requirement.txt ERROR: No matching distribution found for requirement.txt code example

Example: ERROR: Could not find a version that satisfies the requirement cv2 (from versions: none) ERROR: No matching distribution found for cv2

#Know the reason is really dumb, because the reason is that the package of CV2 is not called cv2 but called opencv-python

pip install opencv-python

#For python3:
pip3 install opencv-python