Creates a clam request for the given credential offer.

    The method creates a blinded master secret for a master secret identified by a provided name.
    The master secret identified by the name must be already stored in the secure wallet (see prover_create_master_secret)
    The blinded master secret is a part of the credential request.

    :param wallet_handle: wallet handler (created by open_wallet).
    :param prover_did: a DID of the prover
    :param cred_offer_json: credential offer as a json containing information about the issuer and a credential
    :param cred_def_json: credential definition json related to <cred_def_id> in <cred_offer_json>
    :param master_secret_id: the id of the master secret stored in the wallet
    :return: 
     cred_req_json: Credential request json for creation of credential by Issuer
     {
      "prover_did" : string,
      "cred_def_id" : string,
         // Fields below can depend on Cred Def type
      "blinded_ms" : <blinded_master_secret>,
      "blinded_ms_correctness_proof" : <blinded_ms_correctness_proof>,
      "nonce": string
    }
     cred_req_metadata_json: Credential request metadata json for processing of received form Issuer credential.
        Note: cred_req_metadata_json mustn't be shared with Issuer.

async def prover_create_credential_req(wallet_handle: int,
                                       prover_did: str,
                                       cred_offer_json: str,
                                       cred_def_json: str,
                                       master_secret_id: str) -> (str, str):
    """
    Creates a clam request for the given credential offer.

    The method creates a blinded master secret for a master secret identified by a provided name.
    The master secret identified by the name must be already stored in the secure wallet (see prover_create_master_secret)
    The blinded master secret is a part of the credential request.

    :param wallet_handle: wallet handler (created by open_wallet).
    :param prover_did: a DID of the prover
    :param cred_offer_json: credential offer as a json containing information about the issuer and a credential
    :param cred_def_json: credential definition json related to <cred_def_id> in <cred_offer_json>
    :param master_secret_id: the id of the master secret stored in the wallet
    :return: 
     cred_req_json: Credential request json for creation of credential by Issuer
     {
      "prover_did" : string,
      "cred_def_id" : string,
         // Fields below can depend on Cred Def type
      "blinded_ms" : <blinded_master_secret>,
      "blinded_ms_correctness_proof" : <blinded_ms_correctness_proof>,
      "nonce": string
    }
     cred_req_metadata_json: Credential request metadata json for processing of received form Issuer credential.
        Note: cred_req_metadata_json mustn't be shared with Issuer.
    """

    logger = logging.getLogger(__name__)
    logger.debug("prover_create_credential_req: >>> wallet_handle: %r, prover_did: %r, cred_offer_json: %r,"
                 " cred_def_json: %r, master_secret_id: %r",
                 wallet_handle,
                 prover_did,
                 cred_offer_json,
                 cred_def_json,
                 master_secret_id)

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

    c_wallet_handle = c_int32(wallet_handle)
    c_prover_did = c_char_p(prover_did.encode('utf-8'))
    c_cred_offer_json = c_char_p(cred_offer_json.encode('utf-8'))
    c_cred_def_json = c_char_p(cred_def_json.encode('utf-8'))
    c_master_secret_id = c_char_p(master_secret_id.encode('utf-8'))

    (credential_req_json, credential_req_metadata_json) = await do_call('indy_prover_create_credential_req',
                                                                        c_wallet_handle,
                                                                        c_prover_did,
                                                                        c_cred_offer_json,
                                                                        c_cred_def_json,
                                                                        c_master_secret_id,
                                                                        prover_create_credential_req.cb)

    credential_req_json = credential_req_json.decode()
    credential_req_metadata_json = credential_req_metadata_json.decode()
    res = (credential_req_json, credential_req_metadata_json)

    logger.debug("prover_create_credential_req: <<< res: %r", res)
    return res