code: def is_rfc1918(ip):
      
      if ip_between(ip, "10.0.0.0", "10.255.255.255"):
          return True
      elif ip_between(ip, "172.16.0.0", "172.31.255.255"):
          return True
      elif ip_between(ip, "192.168.0.0", "192.168.255.255"):
          return True
      else:
          return False
docs: Checks to see if an IP address is used for local communications within
      a private network as specified by RFC 1918