docs: def get_bios_firmware_version(snmp_client):
      """Get bios firmware version of the node.
  
      :param snmp_client: an SNMP client object.
      :raises: SNMPFailure if SNMP operation failed.
      :returns: a string of bios firmware version.
      """
  
      try:
          bios_firmware_version = snmp_client.get(BIOS_FW_VERSION_OID)
          return six.text_type(bios_firmware_version)
      except SNMPFailure as e:
          raise SNMPBIOSFirmwareFailure(
              SNMP_FAILURE_MSG % ("GET BIOS FIRMWARE VERSION", e))