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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 makeB64UrlSafe(b64str):
 """ Make a base64 string URL Safe """

    if isinstance(b64str, six.text_type):
        b64str = b64str.encode()
    # see RFC 4648, sec. 5
    return b64str.replace(b'+', b'-').replace(b'/', b'_')