Warning: Silently ignoring app.run() because the application is run from the flask command line executable. Consider putting app.run() behind an if __name__ == "__main__" guard to silence this warning. code example

Example 1: checking for the kernel version... unsupported (18.7.0) configure: error: Valgrind works on Darwin 10.x, 11.x, 12.x, 13.x, 14.x, 15.x, 16.x and 17.x (Mac OS X 10.6/7/8/9/10/11 and macOS 10.12/13)

brew install --HEAD https://raw.githubusercontent.com/sowson/valgrind/master/valgrind.rb

Example 2: Could not build the ssl module! Python requires an OpenSSL 1.0.2 or 1.1 compatible libssl with X509_VERIFY_PARAM_set1_host(). LibreSSL 2.6.4 and earlier do not provide the necessary APIs, https://github.com/libressl-portable/portable/issues/381

$ cd ~
$ wget https://www.openssl.org/source/openssl-1.1.1b.tar.gz
$ wget https://www.openssl.org/source/openssl-1.1.1b.tar.gz.sha256
$ sha256sum openssl-1.1.1b.tar.gz
$ cat openssl-1.1.1b.tar.gz.sha256
$ tar zxvf openssl-1.1.1b.tar.gz
$ ls /home/username/
$ ./config --prefix=/home/username/openssl --openssldir=/home/username/openssl no-ssl2
$ cd openssl-1.1.1b
$ ./config --prefix=/home/username/openssl --openssldir=/home/username/openssl no-ssl2
$ make
$ make test
$ make install
$ cd ~
$ vim ./.bash_profile
$ source .bash_profile
$ which openssl
$ openssl version
$ cd Python-3.7.6
$ ./configure --prefix=$HOME/.local --with-ensurepip=yes CFLAGS="-I$HOME/openssl/include" LDFLAGS="-L$HOME/openssl/lib"
$ make
$ make install
$ source ~/.bash_profile
$ python3 -V