Bad method name...
A simple check whether pip is installed
Rewrite exceptions and dependency resolving/installing loop
Some exception fixes, remove no longer used method
Make the dependencies ordered, system dependencies first
Remove no longer used install_package_manager methods
Remove forgotten try-catch that no longer makes sense here
PackageManager.is_installed means if the package manager itself is installed
Move methods of the two helpers to package_managers + few fixes => almost done