Fix files to make test can pass linting check

Change-Id: Id13a108f20937b542733c5ec9fbf82ee8f004801
diff --git a/scripts/nbhelper.py b/scripts/nbhelper.py
index 8b540dd..d0aa8fa 100644
--- a/scripts/nbhelper.py
+++ b/scripts/nbhelper.py
@@ -174,14 +174,15 @@
         target = None
 
         if not name:
-            target = next(
-                filter(
-                    lambda m: m.data["device_role"]["name"] == "Router",
-                    self.devices + self.vms,
-                )
-            )
+            for machine in self.devices + self.vms:
+                if machine.data["device_role"]["name"] == "Router":
+                    target = machine
+                    break
         else:
-            target = next(filter(lambda m: m.name == name, self.devices + self.vms))
+            for machine in self.devices + self.vms:
+                if machine.name == name:
+                    target = machine
+                    break
 
         return target.generate_netplan()
 
@@ -510,18 +511,12 @@
 
         primary_ip = self.data.primary_ip.address if self.data.primary_ip else None
         primary_if = self.interfaces_by_ip[primary_ip] if primary_ip else None
-        physical_ifs = filter(
-            lambda i: str(i.type) != "Virtual"
-            and i != primary_if
-            and i.mgmt_only == False,
-            self.interfaces,
-        )
 
         self.netplan_config["ethernets"] = dict()
 
         if self.data.device_role.name == "Router":
             for address, interface in self.interfaces_by_ip.items():
-                if interface.mgmt_only == True or str(interface.type) == "Virtual":
+                if interface.mgmt_only is True or str(interface.type) == "Virtual":
                     continue
 
                 self.netplan_config["ethernets"].setdefault(interface.name, {})
@@ -536,7 +531,12 @@
                     "dhcp4-overrides": {"route-metric": 100},
                 }
 
-            for physical_if in physical_ifs:
+            for physical_if in filter(
+                lambda i: str(i.type) != "Virtual"
+                and i != primary_if
+                and i.mgmt_only is False,
+                self.interfaces,
+            ):
                 self.netplan_config["ethernets"][physical_if.name] = {
                     "dhcp4": "yes",
                     "dhcp4-overrides": {"route-metric": 200},
@@ -546,9 +546,7 @@
             return None
 
         # Get interfaces own by AssignedObject and is virtual (VLAN interface)
-        virtual_ifs = filter(lambda i: str(i.type) == "Virtual", self.interfaces)
-
-        for virtual_if in virtual_ifs:
+        for virtual_if in filter(lambda i: str(i.type) == "Virtual", self.interfaces):
             if "vlans" not in self.netplan_config:
                 self.netplan_config["vlans"] = dict()
 
@@ -995,7 +993,7 @@
 
             if mac_addr and mac_addr.strip():  # if exists and not blank
                 self.hosts.append(
-                    {"name": name, "ip_addr": target_ip, "mac_addr": mac_addr.lower(),}
+                    {"name": name, "ip_addr": target_ip, "mac_addr": mac_addr.lower()}
                 )
 
         # add dns servers