mm=255.240.0.x
IP4(mm,24)
j=IP4(mm,24)
x=5
mm
j.substitute(x=1)
j.next_ip()

hh=16#ff
Dec(hh)

h=16#ff + 25
h

IP4Mask(255.240.0.0)
IP4(10.1.280.1)
IP4(10.1.x.1)