You get text

text = '''Ethernet0/0 is up, line protocol is up Description: CUSTOMER A
Internet address is 10.254.60.70/30'''

and you can get IP/MASK using string functions

address = text.split(' ')[-1]
print(address)  # 10.254.60.70/30

and then you can use standard module ipaddress

import ipaddress

net = ipaddress.ip_interface(address)
ip = str(net.network.broadcast_address)
print( ip )   # 10.254.60.71 

or not standard module netaddr

import netaddr

net = netaddr.IPNetwork(address)
ip = str(net.broadcast)
print( ip )   # 10.254.60.71 

EDIT: Minimal working code

text = '''Ethernet0/0 is up, line protocol is up Description: CUSTOMER A
Internet address is 10.254.60.69/30'''

address = text.split(' ')[-1]
print(address)  # 10.254.60.69/30

print('\n--- ipaddress ---\n')

import ipaddress

net = ipaddress.ip_interface(address)

print('ip  :', net.ip )   # 10.254.60.69 
print('ip+1:', net.ip+1 ) # 10.254.60.70
print('ip-1:', net.ip-1 ) # 10.254.60.68

#bip = net.network.broadcast_address
bip = str(net.network.broadcast_address)
print('bip :', bip )      # 10.254.60.71 

print('\n--- netaddr ---\n')

import netaddr

net = netaddr.IPNetwork(address)

print('ip  :', net.ip )   # 10.254.60.69 
print('ip+1:', net.ip+1 ) # 10.254.60.70
print('ip-1:', net.ip-1 ) # 10.254.60.68

bip = net.broadcast
#bip = str(net.broadcast)
print('bip :', bip )      # 10.254.60.71 

Result:

10.254.60.69/30

--- ipaddress ---

ip  : 10.254.60.69
ip+1: 10.254.60.70
ip-1: 10.254.60.68
bip : 10.254.60.71

--- netaddr ---

ip  : 10.254.60.69
ip+1: 10.254.60.70
ip-1: 10.254.60.68
bip : 10.254.60.71