code: def add_device_override(self, addr, cat, subcat, firmware=None):
          
          self.plm.devices.add_override(addr, 'cat', cat)
          self.plm.devices.add_override(addr, 'subcat', subcat)
          if firmware:
              self.plm.devices.add_override(addr, 'firmware', firmware)
docs: Add a device override to the PLM.