(python3) [jiangshan@localhost ~]$ pip install opencv_python==4.1.0
Collecting opencv_python==4.1.0
ERROR: Could not find a version that satisfies the requirement opencv_python==4.1.0 (from versions: 3.4.2.17, 3.4.3.18, 3.4.4.19, 3.4.5.20, 4.0.0.21, 4.0.1.23, 4.0.1.24, 4.1.0.25)
ERROR: No matching distribution found for opencv_python==4.1.0
(python3) [jiangshan@localhost ~]$ pip install opencv_python==4.1.0.25