Try to send an SNMP GET operation using SNMPv3 for the specified OID.

        Parameters
        ----------
        oid : str
            The SNMP OID that you want to get.

        Returns
        -------
        string : str
            The string as part of the value from the OID you are trying to retrieve.

def _get_snmpv3(self, oid):
        """
        Try to send an SNMP GET operation using SNMPv3 for the specified OID.

        Parameters
        ----------
        oid : str
            The SNMP OID that you want to get.

        Returns
        -------
        string : str
            The string as part of the value from the OID you are trying to retrieve.
        """
        snmp_target = (self.hostname, self.snmp_port)
        cmd_gen = cmdgen.CommandGenerator()

        (error_detected, error_status, error_index, snmp_data) = cmd_gen.getCmd(
            cmdgen.UsmUserData(
                self.user,
                self.auth_key,
                self.encrypt_key,
                authProtocol=self.auth_proto,
                privProtocol=self.encryp_proto,
            ),
            cmdgen.UdpTransportTarget(snmp_target, timeout=1.5, retries=2),
            oid,
            lookupNames=True,
            lookupValues=True,
        )

        if not error_detected and snmp_data[0][1]:
            return text_type(snmp_data[0][1])
        return ""