code: def restrict(self, addr):
          
  
          # Remove the address from the set
          ip_addr = _parse_ip(addr)
          if ip_addr is None:
              LOG.warn("Cannot restrict address %r from proxy %s: "
                       "invalid address" % (addr, self.address))
          else:
              self.excluded.add(addr)
docs: Drop an address from the set of addresses this proxy is
          permitted to introduce.
  
          :param addr: The address to remove.