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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 _init_client_authentication( self, client_certchain_file: Optional[str], client_key_file: Optional[str], client_key_type: OpenSslFileTypeEnum, client_key_password: str, ignore_client_authentication_requests: bool ) -> None: """Setup client authentication using the supplied certificate and key. """

        if client_certchain_file is not None and client_key_file is not None:
            self._use_private_key(client_certchain_file, client_key_file, client_key_type, client_key_password)

        if ignore_client_authentication_requests:
            if client_certchain_file:
                raise ValueError('Cannot enable both client_certchain_file and ignore_client_authentication_requests')

            self._ssl_ctx.set_client_cert_cb_NULL()