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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def subfn(pattern, format, string, *args, **kwargs):
 # noqa A002 """Wrapper for `subfn`."""


    flags = args[4] if len(args) > 4 else kwargs.get('flags', 0)
    is_replace = _is_replace(format)
    is_string = isinstance(format, (str, bytes))
    if is_replace and not format.use_format:
        raise ValueError("Compiled replace is not a format object!")

    pattern = compile_search(pattern, flags)
    rflags = FORMAT if is_string else 0
    return _regex.subn(
        pattern, (compile_replace(pattern, format, flags=rflags) if is_replace or is_string else format), string,
        *args, **kwargs
    )