if an import cannot be resolved
    import from fallback package
    
    example:
    from [package_name].doesnt_exist import Foo
    
    results in 
    from [fallback_package_name].doesnt_exist import Foo

def fallbackPackage(package_name, fallback_package_name):
    '''
    if an import cannot be resolved
    import from fallback package
    
    example:
    from [package_name].doesnt_exist import Foo
    
    results in 
    from [fallback_package_name].doesnt_exist import Foo
    
    '''
    importer = Finder(package_name, fallback_package_name)
    sys.meta_path.append(importer)