def METHOD_NAME(fname, *args, **kwargs):
    if fname.endswith('00-base.yml'):
        return io.StringIO(
            u'''
            test: True
            test2:
              child-1: somestring
              child-2: 5
              child-3: False
            test3: True
            test4:
             - abc: 3
             - abc: 4
            ''')
    elif fname.endswith('01-specific.yml'):
        return io.StringIO(
            u'''
            test: False
            test2:
              child-2: 10
              child-3: !!null
            test4:
             - ab: 5
            new-attr: True
            ''')