Question: How to use LibraryTools:-Save?

MyPackageTools := module()
    option package;

    export addPackageDirectoryToLibname, savePackageToMla;

    addPackageDirectoryToLibname := proc(packageDir)

        local mapleInitFile, newLibname:

        mapleInitFile := "/Library/Frameworks/Maple.framework/Versions/2022/lib/init":

        try 
            FileTools:-Text:-Open(mapleInitFile, 'append'):
        catch:
            return "Failed to open file":
        end:

        try
            newLibname := cat("libname := \"", packageDir, "\", libname:" ):
            FileTools:-Text:-WriteLine(mapleInitFile, newLibname):
        catch:
            FileTools:-Text:-Close(mapleInitFile):  
            return "Failed to write to file.": 
        end: 

        try
            FileTools:-Text:-Close(mapleInitFile):   
            return "Added to libname successfully. Restart worksheet for changes to come into effect.":
        catch: 
            return "Failed to close file":
        end:
    end:

    savePackageToMla := proc(mlaPath, mplPath, packageName)

        read(mplPath);

        LibraryTools:-Save(packageName, mlaPath);

    end:
end:

I'd like to automate my workflow a bit. I having a hard time making savePackageToMla work. The commands inside it are the ones I would run in a Maple worksheet to save a package to an .mla file.

The error I get when I try to use this is

Error, (in LibraryTools:-Save) 1st variable is not a name or equation |/Users/marcusegues/maple/Packages/MyPackageTools/MyPackageTools.mpl:38|

Note that the goal is to pass in an mla path and an mpl path. The mpl file is read. The package that is read is the same as the argument packageName. 

I invoke this procedure with something like

savePackageToMla(mlaPath, mplPath, 'MyPackage')

where 

mplPath := '/somePath/MyPackage.mpl';
mlaPath := 'somePath/MyPackage.mla';

and MyPackage.mpl contains something like

MyPackage := module()
  option package;
  (...)
end;