code: def interface_by_ipaddr(self, ipaddr):
          '''
          Given an IP address, return the interface that 'owns' this address
          '''
          ipaddr = IPAddr(ipaddr)
          for devname,iface in self._devinfo.items():
              if iface.ipaddr == ipaddr:
                  return iface
          raise KeyError("No device has IP address {}".format(ipaddr)f interface_by_ipaddr(self, ipaddr):
          '''
          Given an IP address, return the interface that 'owns' this address
          '''
          ipaddr = IPAddr(ipaddr)
          for devname,iface in self._devinfo.items():
              if iface.ipaddr == ipaddr:
                  return iface
          raise KeyError("No device has IP address {}".format(ipaddr))
docs: Given an IP address, return the interface that 'owns' this address