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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 get_http_authentication(private_key: RsaKey, private_key_id: str) -> HTTPSignatureHeaderAuth: """ Get HTTP signature authentication for a request. """

    key = private_key.exportKey()
    return HTTPSignatureHeaderAuth(
        headers=["(request-target)", "user-agent", "host", "date"],
        algorithm="rsa-sha256",
        key=key,
        key_id=private_key_id,
    )