diff --git a/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/Invocation.java b/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/Invocation.java
index fa477df..972e7cd 100644
--- a/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/Invocation.java
+++ b/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/Invocation.java
@@ -298,7 +298,12 @@ public String toScript() throws NotBoundException, NotDerivableException {
 		// report stage in file sizes and report error when something is missing
 		buf.append( comment( "report stage in file sizes and report error when something is missing" ) );
 		buf.append( getStageInCollect() ).append( '\n' );
-				
+		
+		// insert body prefix
+		buf.append( comment( "insert body prefix" ) );
+		buf.append( getBodyPrefix() ).append( '\n' );
+		
+		
 		// insert function body
 		buf.append( comment( "insert function body" ) );
 		buf.append( ticket.getBody() ).append( '\n' );
@@ -332,6 +337,11 @@ protected String declareString( String outputName ) {
 	protected String getImport() {
 		return "";
 	}
+	
+	@SuppressWarnings("static-method")
+	protected String getBodyPrefix() {
+		return "";
+	}
 
 	protected abstract String callFunction( String name, String... argValue );
 	protected abstract String callProcedure( String name, String... argValue );
diff --git a/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/PythonInvocation.java b/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/PythonInvocation.java
index 0a202b2..81679d6 100644
--- a/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/PythonInvocation.java
+++ b/cuneiform-core/src/main/java/de/huberlin/wbi/cuneiform/core/invoc/PythonInvocation.java
@@ -137,6 +137,11 @@ protected String forEach( String listName, String elementName, String body ) {
 			"for "+elementName+" in "+listName+":\n    "
 			+body.replace( "\n", "\n    " )+"\n";
 	}
+	
+	@Override
+	protected String getBodyPrefix() {
+		return "if True:\n";
+	}
 
 	@Override
 	protected String getImport() {