code: def check (self):
          
          if self.aggregate.config["trace"]:
              trace.trace_on()
          try:
              self.local_check()
          except (socket.error, select.error):
              # on Unix, ctrl-c can raise
              # error: (4, 'Interrupted system call')
              etype, value = sys.exc_info()[:2]
              if etype == errno.EINTR:
                  raise KeyboardInterrupt(value)
              else:
                  raise
docs: Main check function for checking this URL.