Environment    raspbian: jessie    Linux phome 4.9.35-v7+ #1014 SMP   Goal:    To setup Jupyter Notebook.    (needed pip3 18.1. (It required Python 3.5 but mine is 3.4.2)   Conclusion:    - Python-3.6.11 : OK    - Python-3.8.3       make : OK, but pip cannot connect TLS/SSL        ( https://stackoverflow.com/questions/62827291/warning-pip-is-configured-with-locations-that-require-tls-ssl-however-the-ssl )       I think that it occurred by the difference of  openssl versions.       (But I did not to try figure out)     - Python-3.7.4 : Same problem like 3.8.3.     - Python-3.5.9 : Compile error by gcov dependency.   Method:    - Download 3.6.11 source and compile.    - Type "make altinstall"    - Make file links with "update-alternatives" command.