diff --git a/src/XML-Writer-Core/XMLAttributeDeclarationWriter.class.st b/src/XML-Writer-Core/XMLAttributeDeclarationWriter.class.st
index 6bfce20..3b90c19 100644
--- a/src/XML-Writer-Core/XMLAttributeDeclarationWriter.class.st
+++ b/src/XML-Writer-Core/XMLAttributeDeclarationWriter.class.st
@@ -40,7 +40,7 @@ XMLAttributeDeclarationWriter >> defaultPragma [
 { #category : #accessing }
 XMLAttributeDeclarationWriter >> defaultPragma: aDefaultPragma [
 
-	defaultPragma := (aDefaultPragma notNil and: [
+	defaultPragma := (aDefaultPragma isNotNil and: [
 		                  aDefaultPragma notEmpty and: [
 			                  aDefaultPragma first == $# ] ])
 		                 ifTrue: [ aDefaultPragma allButFirst ]
diff --git a/src/XML-Writer-Core/XMLMarkupWriter.class.st b/src/XML-Writer-Core/XMLMarkupWriter.class.st
index 42ca018..f0d5f3b 100644
--- a/src/XML-Writer-Core/XMLMarkupWriter.class.st
+++ b/src/XML-Writer-Core/XMLMarkupWriter.class.st
@@ -104,7 +104,7 @@ XMLMarkupWriter >> isDoctypeDeclarationWriter [
 { #category : #testing }
 XMLMarkupWriter >> isEmbedded [
 
-	^ self parent notNil
+	^ self parent isNotNil
 ]
 
 { #category : #testing }
diff --git a/src/XML-Writer-Core/XMLTagWriter.class.st b/src/XML-Writer-Core/XMLTagWriter.class.st
index b7b55cd..15299fc 100644
--- a/src/XML-Writer-Core/XMLTagWriter.class.st
+++ b/src/XML-Writer-Core/XMLTagWriter.class.st
@@ -57,13 +57,13 @@ XMLTagWriter >> attributes: anAssociationCollection [
 { #category : #testing }
 XMLTagWriter >> hasAttributes [
 
-	^ attributes notNil and: [ attributes notEmpty ]
+	^ attributes isNotNil and: [ attributes notEmpty ]
 ]
 
 { #category : #testing }
 XMLTagWriter >> hasXMLNSDeclarations [
 
-	^ xmlnsDeclarations notNil and: [ xmlnsDeclarations notEmpty ]
+	^ xmlnsDeclarations isNotNil and: [ xmlnsDeclarations notEmpty ]
 ]
 
 { #category : #testing }
diff --git a/src/XML-Writer-Core/XMLUnsafeStartTagWriter.class.st b/src/XML-Writer-Core/XMLUnsafeStartTagWriter.class.st
index bd5dcd3..a7c6db1 100644
--- a/src/XML-Writer-Core/XMLUnsafeStartTagWriter.class.st
+++ b/src/XML-Writer-Core/XMLUnsafeStartTagWriter.class.st
@@ -52,13 +52,13 @@ XMLUnsafeStartTagWriter >> attributes: anAssociationCollection [
 { #category : #testing }
 XMLUnsafeStartTagWriter >> hasAttributes [
 
-	^ attributes notNil and: [ attributes notEmpty ]
+	^ attributes isNotNil and: [ attributes notEmpty ]
 ]
 
 { #category : #testing }
 XMLUnsafeStartTagWriter >> hasXMLNSDeclarations [
 
-	^ xmlnsDeclarations notNil and: [ xmlnsDeclarations notEmpty ]
+	^ xmlnsDeclarations isNotNil and: [ xmlnsDeclarations notEmpty ]
 ]
 
 { #category : #testing }
diff --git a/src/XML-Writer-Core/XMLWriter.class.st b/src/XML-Writer-Core/XMLWriter.class.st
index 37d9325..8131c2c 100644
--- a/src/XML-Writer-Core/XMLWriter.class.st
+++ b/src/XML-Writer-Core/XMLWriter.class.st
@@ -634,8 +634,8 @@ XMLWriter >> entityValueEscapes [
 { #category : #testing }
 XMLWriter >> escapesContentEntityReferences [
 	^ self isEscaping
-		and: [(contentEscapes at: $& asciiValue) notNil
-			and: [(contentStringEscapes at: $& asciiValue) notNil]]
+		and: [(contentEscapes at: $& asciiValue) isNotNil
+			and: [(contentStringEscapes at: $& asciiValue) isNotNil]]
 ]
 
 { #category : #accessing }
@@ -792,12 +792,12 @@ XMLWriter >> hadActiveTagWriter [
 
 { #category : #testing }
 XMLWriter >> hasActiveTagWriter [
-	^ self activeTagWriter notNil
+	^ self activeTagWriter isNotNil
 ]
 
 { #category : #testing }
 XMLWriter >> hasFormatter [
-	^ formatter notNil
+	^ formatter isNotNil
 ]
 
 { #category : #testing }
@@ -1175,7 +1175,7 @@ XMLWriter >> write: aString escapedWith: anEscapeTable [
 		| nextChar asciiValue |
 		((asciiValue := (nextChar := aString at: i) asciiValue) > 0 and: [
 			 asciiValue <= tableSize and: [
-				 (anEscapeTable at: asciiValue) notNil ] ])
+				 (anEscapeTable at: asciiValue) isNotNil ] ])
 			ifTrue: [
 				| replacement |
 				(replacement := anEscapeTable at: asciiValue) == #LineBreak