def METHOD_NAME(
    test_target: Optional[str] = None
) -> List[unittest.TestSuite]:
    """Creates test suites. If test_target is None, runs all tests.
    Args:
        test_target: str. The name of the test script.
            Default to None if not specified.
    Returns:
        list. A list of tests within the test script.
    Raises:
        Exception. The delimeter in the test_target should be a dot (.)
    """
    if test_target and '/' in test_target:
        raise Exception('The delimiter in test_target should be a dot (.)')
    loader = unittest.TestLoader()
    master_test_suite = (
        loader.loadTestsFromName(test_target)
        if test_target else
        loader.discover(
            CURR_DIR,
            pattern='[^core/tests/data]*_test.py',
            top_level_dir=CURR_DIR
        )
    )
    return [master_test_suite]