Best way to obfuscate python code?

Hi, what is the best way to prevent someone from reading and editing python code?
I tried py2exe, pyinstaller and cx_freeze to create an executable. I got the executables, but they don't run.
I also looked into compiling the .py file into a .pyc file, but found on the internet, that these files are relatively easy to decompile.
Is importing and password protecting the script my only option? And how safe is that?
Thanks