code: def verify_counter(self, signature, counter):
           
  
          devices = self.__get_u2f_devices()
  
          for device in devices:
              # Searching for specific keyhandle
              if device['keyHandle'] == signature['keyHandle']:
                  if counter > device['counter']:
                      
                      # Updating counter record
                      device['counter'] = counter
                      self.__save_u2f_devices(devices)
                      
                      return True
                  else:
                      return False
docs: Verifies that counter value is greater than previous signature