diff --git a/transforms/templates/interface_yang.j2 b/transforms/templates/interface_yang.j2
index f0164ea..2739c2b 100644
--- a/transforms/templates/interface_yang.j2
+++ b/transforms/templates/interface_yang.j2
@@ -17,9 +17,9 @@
   {%- set _ = interfaces.append({
     "type": "loopback",
     "name": iface.name.value,
-    "description": iface.description.value,
+    "description": iface.description.value | default(none),
     "enabled": iface.enabled.value,
-    "mtu": iface.mtu.value,
+    "mtu": iface.mtu.value | default(none),
     "ip_addresses": ip_list
   }) -%}
 {%- endfor -%}
@@ -31,18 +31,18 @@
   {%- for ip_edge in iface.ip_addresses.edges -%}
     {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
   {%- endfor -%}
-  {%- set lag_name = null -%}
-  {%- if iface.lag and iface.lag.node -%}
+  {%- set lag_name = none -%}
+  {%- if iface.lag is defined and iface.lag is not none and iface.lag.node is not none -%}
     {%- set lag_name = iface.lag.node.name.value -%}
   {%- endif -%}
   {%- set _ = interfaces.append({
     "type": "ethernet",
     "name": iface.name.value,
-    "description": iface.description.value,
+    "description": iface.description.value | default(none),
     "enabled": iface.enabled.value,
-    "mtu": iface.mtu.value,
-    "speed": iface.speed.value,
-    "mode": iface.mode.value,
+    "mtu": iface.mtu.value | default(none),
+    "speed": iface.speed.value | default(none),
+    "mode": iface.mode.value | default(none),
     "lag": lag_name,
     "ip_addresses": ip_list
   }) -%}
@@ -55,18 +55,18 @@
   {%- for ip_edge in iface.ip_addresses.edges -%}
     {%- set _ = ip_list.append(ip_edge.node.address.value) -%}
   {%- endfor -%}
-  {%- set vlan_id = null -%}
-  {%- if iface.vlan and iface.vlan.node -%}
+  {%- set vlan_id = none -%}
+  {%- if iface.vlan is defined and iface.vlan is not none and iface.vlan.node is not none -%}
     {%- set vlan_id = iface.vlan.node.vlan_id.value -%}
   {%- endif -%}
   {%- set _ = interfaces.append({
     "type": "vlan",
     "name": iface.name.value,
-    "description": iface.description.value,
+    "description": iface.description.value | default(none),
     "enabled": iface.enabled.value,
-    "mtu": iface.mtu.value,
+    "mtu": iface.mtu.value | default(none),
     "vlan_id": vlan_id,
-    "virtual_router_address": iface.virtual_router_address.value,
+    "virtual_router_address": iface.virtual_router_address.value | default(none),
     "autostate": iface.autostate.value,
     "ip_addresses": ip_list
   }) -%}
@@ -86,11 +86,11 @@
   {%- set _ = interfaces.append({
     "type": "lag",
     "name": iface.name.value,
-    "description": iface.description.value,
+    "description": iface.description.value | default(none),
     "enabled": iface.enabled.value,
-    "mtu": iface.mtu.value,
-    "lacp_mode": iface.lacp_mode.value,
-    "mlag_id": iface.mlag_id.value,
+    "mtu": iface.mtu.value | default(none),
+    "lacp_mode": iface.lacp_mode.value | default(none),
+    "mlag_id": iface.mlag_id.value | default(none),
     "members": member_list,
     "ip_addresses": ip_list
   }) -%}
diff --git a/transforms/templates/vlan_yang.j2 b/transforms/templates/vlan_yang.j2
index bd7a057..423fc02 100644
--- a/transforms/templates/vlan_yang.j2
+++ b/transforms/templates/vlan_yang.j2
@@ -16,18 +16,18 @@
     {%- set vlan_node = mapping_edge.node.vlan.node -%}
     {%- set vid = vlan_node.vlan_id.value | string -%}
     {%- if vid not in vlans -%}
-      {%- set vni_val = null -%}
-      {%- set vni_type_val = null -%}
-      {%- if vlan_node.vni and vlan_node.vni.node -%}
+      {%- set vni_val = none -%}
+      {%- set vni_type_val = none -%}
+      {%- if vlan_node.vni is defined and vlan_node.vni is not none and vlan_node.vni.node is not none -%}
         {%- set vni_val = vlan_node.vni.node.vni.value -%}
         {%- set vni_type_val = vlan_node.vni.node.vni_type.value -%}
       {%- endif -%}
       {%- set _ = vlans.update({vid: {
         "vlan_id": vlan_node.vlan_id.value,
         "name": vlan_node.name.value,
-        "status": vlan_node.status.value | upper,
-        "vlan_type": vlan_node.vlan_type.value,
-        "trunk_groups": vlan_node.trunk_groups.value if vlan_node.trunk_groups.value else [],
+        "status": vlan_node.status.value | default('') | upper,
+        "vlan_type": vlan_node.vlan_type.value | default(none),
+        "trunk_groups": vlan_node.trunk_groups.value | default([]),
         "stp_enabled": vlan_node.stp_enabled.value,
         "vni": vni_val,
         "vni_type": vni_type_val
@@ -38,22 +38,22 @@
 
 {#— Collect VLANs from SVI interfaces —#}
 {%- for svi_edge in data.InfraInterfaceVlan.edges -%}
-  {%- if svi_edge.node.vlan and svi_edge.node.vlan.node -%}
+  {%- if svi_edge.node.vlan is defined and svi_edge.node.vlan is not none and svi_edge.node.vlan.node is not none -%}
     {%- set vlan_node = svi_edge.node.vlan.node -%}
     {%- set vid = vlan_node.vlan_id.value | string -%}
     {%- if vid not in vlans -%}
-      {%- set vni_val = null -%}
-      {%- set vni_type_val = null -%}
-      {%- if vlan_node.vni and vlan_node.vni.node -%}
+      {%- set vni_val = none -%}
+      {%- set vni_type_val = none -%}
+      {%- if vlan_node.vni is defined and vlan_node.vni is not none and vlan_node.vni.node is not none -%}
         {%- set vni_val = vlan_node.vni.node.vni.value -%}
         {%- set vni_type_val = vlan_node.vni.node.vni_type.value -%}
       {%- endif -%}
       {%- set _ = vlans.update({vid: {
         "vlan_id": vlan_node.vlan_id.value,
         "name": vlan_node.name.value,
-        "status": vlan_node.status.value | upper,
-        "vlan_type": vlan_node.vlan_type.value,
-        "trunk_groups": vlan_node.trunk_groups.value if vlan_node.trunk_groups.value else [],
+        "status": vlan_node.status.value | default('') | upper,
+        "vlan_type": vlan_node.vlan_type.value | default(none),
+        "trunk_groups": vlan_node.trunk_groups.value | default([]),
         "stp_enabled": vlan_node.stp_enabled.value,
         "vni": vni_val,
         "vni_type": vni_type_val
diff --git a/transforms/templates/vxlan_yang.j2 b/transforms/templates/vxlan_yang.j2
index 62f3280..c57d036 100644
--- a/transforms/templates/vxlan_yang.j2
+++ b/transforms/templates/vxlan_yang.j2
@@ -10,8 +10,8 @@
 {#— Build VTEP section (there is one VTEP per device) —#}
 {%- if vtep_edges | length > 0 -%}
   {%- set vtep = vtep_edges[0].node -%}
-  {%- set source_iface = null -%}
-  {%- if vtep.source_interface and vtep.source_interface.node -%}
+  {%- set source_iface = none -%}
+  {%- if vtep.source_interface is defined and vtep.source_interface is not none and vtep.source_interface.node is not none -%}
     {%- set source_iface = vtep.source_interface.node.name.value -%}
   {%- endif -%}
 
@@ -19,15 +19,15 @@
   {%- set vlan_vni_list = [] -%}
   {%- for mapping_edge in vtep.vlan_vni_mappings.edges -%}
     {%- set m = mapping_edge.node -%}
-    {%- set vlan_id = null -%}
-    {%- set vlan_name = null -%}
-    {%- if m.vlan and m.vlan.node -%}
+    {%- set vlan_id = none -%}
+    {%- set vlan_name = none -%}
+    {%- if m.vlan is defined and m.vlan is not none and m.vlan.node is not none -%}
       {%- set vlan_id = m.vlan.node.vlan_id.value -%}
       {%- set vlan_name = m.vlan.node.name.value -%}
     {%- endif -%}
-    {%- set vni_val = null -%}
-    {%- set vni_type_val = null -%}
-    {%- if m.vni and m.vni.node -%}
+    {%- set vni_val = none -%}
+    {%- set vni_type_val = none -%}
+    {%- if m.vni is defined and m.vni is not none and m.vni.node is not none -%}
       {%- set vni_val = m.vni.node.vni.value -%}
       {%- set vni_type_val = m.vni.node.vni_type.value -%}
     {%- endif -%}
@@ -43,14 +43,14 @@
   {%- set vrf_vni_list = [] -%}
   {%- for vrf_edge in vrf_edges -%}
     {%- set assignment = vrf_edge.node -%}
-    {%- set vrf_name = null -%}
-    {%- set l3vni = null -%}
+    {%- set vrf_name = none -%}
+    {%- set l3vni = none -%}
     {%- set import_rts = [] -%}
     {%- set export_rts = [] -%}
-    {%- if assignment.vrf and assignment.vrf.node -%}
+    {%- if assignment.vrf is defined and assignment.vrf is not none and assignment.vrf.node is not none -%}
       {%- set vrf_node = assignment.vrf.node -%}
       {%- set vrf_name = vrf_node.name.value -%}
-      {%- if vrf_node.l3vni and vrf_node.l3vni.node -%}
+      {%- if vrf_node.l3vni is defined and vrf_node.l3vni is not none and vrf_node.l3vni.node is not none -%}
         {%- set l3vni = vrf_node.l3vni.node.vni.value -%}
       {%- endif -%}
       {%- for rt_edge in vrf_node.import_targets.edges -%}
@@ -63,7 +63,7 @@
     {%- set _ = vrf_vni_list.append({
       "vrf": vrf_name,
       "l3vni": l3vni,
-      "route_distinguisher": assignment.route_distinguisher.value,
+      "route_distinguisher": assignment.route_distinguisher.value | default(none),
       "import_targets": import_rts,
       "export_targets": export_rts
     }) -%}
@@ -74,14 +74,14 @@
       "source_address": vtep.source_address.value,
       "source_interface": source_iface,
       "udp_port": vtep.udp_port.value,
-      "learn_restrict": vtep.learn_restrict.value,
+      "learn_restrict": vtep.learn_restrict.value | default(none),
       "vlan_vni_mappings": vlan_vni_list | sort(attribute='vlan_id'),
       "vrf_vni_mappings": vrf_vni_list
     }
   } -%}
 {%- else -%}
   {%- set result = {
-    "vtep": null,
+    "vtep": none,
     "vrf_vni_mappings": []
   } -%}
 {%- endif -%}