diff --git a/engine/src/main/java/pro/verron/officestamper/api/OfficeStamperConfiguration.java b/engine/src/main/java/pro/verron/officestamper/api/OfficeStamperConfiguration.java
index 8d4320a0..f8786bf2 100644
--- a/engine/src/main/java/pro/verron/officestamper/api/OfficeStamperConfiguration.java
+++ b/engine/src/main/java/pro/verron/officestamper/api/OfficeStamperConfiguration.java
@@ -46,9 +46,7 @@ OfficeStamperConfiguration addCommentProcessor(
      *
      * @param preprocessor the pre-processor to add
      */
-    void addPreprocessor(PreProcessor preprocessor);
-
-
+    OfficeStamperConfiguration addPreprocessor(PreProcessor preprocessor);
 
     /**
      * Retrieves the EvaluationContextConfigurer for configuring the Spring Expression Language (SPEL) EvaluationContext
@@ -152,5 +150,5 @@ <T, U, V> NeedsTriFunctionImpl<T, U, V> addCustomFunction(
 
     List<PostProcessor> getPostprocessors();
 
-    void addPostprocessor(PostProcessor postProcessor);
+    OfficeStamperConfiguration addPostprocessor(PostProcessor postProcessor);
 }
diff --git a/engine/src/main/java/pro/verron/officestamper/core/DocumentUtil.java b/engine/src/main/java/pro/verron/officestamper/core/DocumentUtil.java
index d95cff5f..26b7c3ee 100644
--- a/engine/src/main/java/pro/verron/officestamper/core/DocumentUtil.java
+++ b/engine/src/main/java/pro/verron/officestamper/core/DocumentUtil.java
@@ -16,6 +16,7 @@
 import org.springframework.util.function.ThrowingFunction;
 import pro.verron.officestamper.api.DocxPart;
 import pro.verron.officestamper.api.OfficeStamperException;
+import pro.verron.officestamper.api.Paragraph;
 
 import java.util.*;
 import java.util.stream.Stream;
@@ -38,13 +39,6 @@ private DocumentUtil() {
         throw new OfficeStamperException("Utility classes shouldn't be instantiated");
     }
 
-    public static <T> Stream<T> streamObjectElements(DocxPart source, Class<T> elementClass) {
-        ClassFinder finder = new ClassFinder(elementClass);
-        TraversalUtil.visit(source.part(), finder);
-        return finder.results.stream()
-                             .map(elementClass::cast);
-    }
-
     /**
      * Retrieve the last element from an object.
      *
@@ -213,4 +207,22 @@ private static Stream<JaxbXmlPart<?>> extractHeaderFooterParts(HeaderFooterPolic
         ofNullable(hfp.getEvenFooter()).ifPresent(builder::add);
         return builder.build();
     }
+
+    static Stream<Paragraph> streamParagraphs(TextualDocxPart source) {
+        var paragraphs = streamObjectElements(source, P.class)
+                .map(p -> StandardParagraph.from(source, p));
+        var sdtRuns = streamObjectElements(source, SdtRun.class)
+                .map(SdtRun::getSdtContent)
+                .filter(CTSdtContentRun.class::isInstance)
+                .map(CTSdtContentRun.class::cast)
+                .map(paragraph -> StandardParagraph.from(source, paragraph));
+        return Stream.concat(paragraphs, sdtRuns);
+    }
+
+    public static <T> Stream<T> streamObjectElements(DocxPart source, Class<T> elementClass) {
+        ClassFinder finder = new ClassFinder(elementClass);
+        TraversalUtil.visit(source.part(), finder);
+        return finder.results.stream()
+                             .map(elementClass::cast);
+    }
 }
diff --git a/engine/src/main/java/pro/verron/officestamper/core/DocxStamperConfiguration.java b/engine/src/main/java/pro/verron/officestamper/core/DocxStamperConfiguration.java
index abaadca6..69a73352 100644
--- a/engine/src/main/java/pro/verron/officestamper/core/DocxStamperConfiguration.java
+++ b/engine/src/main/java/pro/verron/officestamper/core/DocxStamperConfiguration.java
@@ -65,7 +65,7 @@ public void resetResolvers() {
     ///
     /// @param interfaceClass the interface holding methods to expose in the expression language.
     /// @param implementation the implementation to call to evaluate invocations of those methods.
-    ///                          Must implement the mentioned interface.
+    ///                       Must implement the mentioned interface.
     ///
     /// @return a [DocxStamperConfiguration] object
     @Override
@@ -96,9 +96,9 @@ public DocxStamperConfiguration addCommentProcessor(
     ///
     /// @param preprocessor the preprocessor to add.
     @Override
-    public void addPreprocessor(PreProcessor preprocessor) {
+    public OfficeStamperConfiguration addPreprocessor(PreProcessor preprocessor) {
         preprocessors.add(preprocessor);
-
+        return this;
     }
 
     @Override
@@ -239,7 +239,8 @@ public List<PostProcessor> getPostprocessors() {
     }
 
     @Override
-    public void addPostprocessor(PostProcessor postprocessor) {
+    public OfficeStamperConfiguration addPostprocessor(PostProcessor postprocessor) {
         postprocessors.add(postprocessor);
+        return this;
     }
 }
diff --git a/engine/src/main/java/pro/verron/officestamper/core/TextualDocxPart.java b/engine/src/main/java/pro/verron/officestamper/core/TextualDocxPart.java
index 5eb6f69c..780547d8 100644
--- a/engine/src/main/java/pro/verron/officestamper/core/TextualDocxPart.java
+++ b/engine/src/main/java/pro/verron/officestamper/core/TextualDocxPart.java
@@ -4,7 +4,9 @@
 import org.docx4j.openpackaging.parts.Part;
 import org.docx4j.openpackaging.parts.relationships.RelationshipsPart;
 import org.docx4j.relationships.Relationship;
-import org.docx4j.wml.*;
+import org.docx4j.wml.ContentAccessor;
+import org.docx4j.wml.P;
+import org.docx4j.wml.R;
 import pro.verron.officestamper.api.DocxPart;
 import pro.verron.officestamper.api.Paragraph;
 
@@ -33,13 +35,7 @@ public TextualDocxPart(
 
 
     public Stream<Paragraph> streamParagraphs() {
-        return Stream.concat(DocumentUtil.streamObjectElements(this, P.class)
-                                         .map(p -> StandardParagraph.from(this, p)),
-                DocumentUtil.streamObjectElements(this, SdtRun.class)
-                                    .map(SdtRun::getSdtContent)
-                                    .filter(CTSdtContentRun.class::isInstance)
-                                    .map(CTSdtContentRun.class::cast)
-                                    .map(paragraph -> StandardParagraph.from(this, paragraph)));
+        return DocumentUtil.streamParagraphs(this);
     }
 
     @Override public Stream<R> streamRun() {