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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 tar_add_bytes(tf, filename, bytestring):
 """ Add a file to a tar archive Args: tf (tarfile.TarFile):
 tarfile to add the file to filename (str):
 path within the tar file bytestring (bytes or str):
 file contents. Must be :class:`bytes` or ascii-encodable :class:`str` """

    if not isinstance(bytestring, bytes):  # it hasn't been encoded yet
        bytestring = bytestring.encode('ascii')
    buff = io.BytesIO(bytestring)
    tarinfo = tarfile.TarInfo(filename)
    tarinfo.size = len(bytestring)
    tf.addfile(tarinfo, buff)