[docker] docker run <IMAGE> <MULTIPLE COMMANDS>

Just to make a proper answer from the @Eddy Hernandez's comment and which is very correct since Alpine comes with ash not bash.

The question now referes to Starting a shell in the Docker Alpine container which implies using sh or ash or /bin/sh or /bin/ash/.

Based on the OP's question:

docker run image sh -c "cd /path/to/somewhere && python a.py"