replaced old string formatting with fstrings

inventory_provider/routes/ims_classifier.py

@@ -110,7 +110,7 @@ def after_request(resp):
 
 def related_interfaces(hostname, interface):
     r = common.get_current_redis()
-    prefix = 'netconf-interfaces:%s:' % hostname
+    prefix = f'netconf-interfaces:{hostname}:'
     for k in r.keys(prefix + interface + '.*'):
         k = k.decode('utf-8')
         assert k.startswith(prefix)  # sanity
@@ -263,7 +263,7 @@ def ix_peering_info(peer_info):
         address = ipaddress.ip_address(peer_info['name'])
     except ValueError:
         raise ClassifierProcessingError(
-            'unable to parse %r as an ip address' % address)
+            f'unable to parse {address} as an ip address')
 
     description = peer_info['description']
     assert description is not None  # sanity
@@ -373,7 +373,7 @@ def peer_info(address):
             result['ix-public-peer-info'] = ix_peering_info(info)
             result['locations'] += _location_from_equipment(info['router'])
 
-        info = r.get('vpn_rr_peer:%s' % address)
+        info = r.get(f'vpn_rr_peer:{address}')
         if info:
             info = info.decode('utf-8')
             info = json.loads(info)