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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:
 async def build_attrib_request(submitter_did: str, target_did: str, xhash: Optional[str], raw: Optional[str], enc: Optional[str]) -> str: """ Builds an ATTRIB request. Request to add attribute to a NYM record. :param submitter_did: DID of the submitter stored in secured Wallet. :param target_did: Target DID as base58-encoded string for 16 or 32 bit DID value. :param xhash: (Optional) Hash of attribute data. :param raw: (Optional) Json, where key is attribute name and value is attribute value. :param enc: (Optional) Encrypted value attribute data. :return: Request result as json. """


    logger = logging.getLogger(__name__)
    logger.debug("build_attrib_request: >>> submitter_did: %r, target_did: %r, hash: %r, raw: %r, enc: %r",
                 submitter_did,
                 target_did,
                 xhash,
                 raw,
                 enc)

    if not hasattr(build_attrib_request, "cb"):
        logger.debug("build_attrib_request: Creating callback")
        build_attrib_request.cb = create_cb(CFUNCTYPE(None, c_int32, c_int32, c_char_p))

    c_submitter_did = c_char_p(submitter_did.encode('utf-8'))
    c_target_did = c_char_p(target_did.encode('utf-8'))
    c_hash = c_char_p(xhash.encode('utf-8')) if xhash is not None else None
    c_raw = c_char_p(raw.encode('utf-8')) if raw is not None else None
    c_enc = c_char_p(enc.encode('utf-8')) if enc is not None else None

    request_json = await do_call('indy_build_attrib_request',
                                 c_submitter_did,
                                 c_target_did,
                                 c_hash,
                                 c_raw,
                                 c_enc,
                                 build_attrib_request.cb)

    res = request_json.decode()
    logger.debug("build_attrib_request: <<< res: %r", res)
    return res