diff --git a/docs/eml_model.png b/docs/eml_model.png
index a8b1909..075de65 100644
Binary files a/docs/eml_model.png and b/docs/eml_model.png differ
diff --git a/docs/eml_model.puml b/docs/eml_model.puml
index bc9c41e..10ce30e 100644
--- a/docs/eml_model.puml
+++ b/docs/eml_model.puml
@@ -75,7 +75,7 @@ class contact {
 class individualName_contact {
     name: 'individualName'
     attributes: {}
-    contents: None
+    content: None
     parent: creator
     children: [surName_contact]
 }
@@ -83,7 +83,7 @@ class individualName_contact {
 class surName_contact {
     name: 'surName'
     attributes: {}
-    contents: 'Gaucho'
+    content: 'Gaucho'
     parent: individualName_contact
     children: []
 }
@@ -91,7 +91,7 @@ class surName_contact {
 class individualName_creator {
     name: 'individualName'
     attributes: {}
-    contents: None
+    content: None
     parent: creator
     children: [surName_creator]
 }
@@ -99,7 +99,7 @@ class individualName_creator {
 class surName_creator {
     name: 'surName'
     attributes: {}
-    contents: 'Gaucho'
+    content: 'Gaucho'
     parent: individualName_creator
     children: []
 }
diff --git a/src/metapype/eml/validate.py b/src/metapype/eml/validate.py
index 9610240..dc01daa 100644
--- a/src/metapype/eml/validate.py
+++ b/src/metapype/eml/validate.py
@@ -30,15 +30,16 @@ def node(node: Node, errs: list=None) -> None:
 
     Args:
         node: Node instance to be validated
+        errs: List container for validation errors (fail fast if None)
 
     Returns:
         None
 
     Raises:
-        MetapypeRuleError: An unknown type of node for EML 2.1.1
+        MetapypeRuleError: An unknown type of node for EML
     """
     if node.name not in rule.node_mappings:
-        msg = "Unknown node: {}".format(node.name)
+        msg = f"Unknown node rule type: {node.name}"
         if errs is None:
             raise MetapypeRuleError(msg)
         else: