Modulenotfounderror: no module named 'rospy', PIP could not find the installation package

Running an open source python Script error
ERROR: Could not find a version that satisfies the requirement rospy
Direct use pip install rospy No suitable installation package was found
I use watercress , In fact, there is no package in the source , Need to use other pip Source , Follow the command below
pip install --extra-index-url https://rospypi.github.io/simple/ rosbag
Installation is OK , Other such as cv_bridge It's the same thing , If the network is slow or Q, The use of Science li You can install it in the way of , as follows （ You need to configure the generation in advance li The server can be used proxychains4）
proxychains4 pip install --extra-index-url https://rospypi.github.io/simple/ rosbag cv_bridge