I get this message whenever I install using pip
Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/usr/local/lib/python3.5/dist-packages/Markdown-2.6.11.dist-info'
Consider using the `--user` option or check the permissions.
I also get these kind of message said this is not capatable.
requests 2.18.4 has requirement idna<2.7,>=2.5, but you'll have idna 2.7 which is incompatible.
requests 2.18.4 has requirement urllib3<1.23,>=1.21.1, but you'll have urllib3 1.23 which is incompatible.
Why does it happen? How can I solve this problem?