how to report missing files in a list, usable in python script? Is there any simple way to get all missing .blend libraries, in a python list, set, tuple or dictionary?

The operator bpy.ops.file.report_missing_files() only prints this list in the console. If I put it in a variable, the only thing I have is a set: {'FINISHED'} !! To illustrate:

missing_libs = bpy.ops.file.report_missing_files()
# missing libraries are printed in the console at this point, one line a file
print(missing_libs)
# prints {'FINISHED'} in the console


Ideally, I want to be able to do, for example:

nb_missing_libs = len(missing_libs) # get the number of missing libraries
for mlib in missing_libs:
    if ".blend" in mlib:
        # Do something with mlib


Is there a fast and easy way ?
You could try a variation of the following code:

import bpy
import os

def list_missing_blend_libs():
    return [bpy.path.abspath(lib.filepath) for lib in bpy.data.libraries
            if not os.path.exists(bpy.path.abspath(lib.filepath))]


Using bpy.path.abspath, it only lists absolute path of missing libraries in bpy.data.libraries.