diff --git a/contributors.txt b/contributors.txt
index 07a894eda..7293713a0 100644
--- a/contributors.txt
+++ b/contributors.txt
@@ -88,5 +88,6 @@ YYYY/MM/DD, github id, Full name, email
 2015/12/17, sebadur, Sebastian Badur, sebadur@users.noreply.github.com
 2015/12/23, pboyer, Peter Boyer, peter.b.boyer@gmail.com
 2015/12/24, dtymon, David Tymon, david.tymon@gmail.com
+2016/02/18, reitzig, Raphael Reitzig, reitzig[at]cs.uni-kl.de
 2016/03/27, beardlybread, Bradley Steinbacher, bradley.j.steinbacher@gmail.com
 2016/03/28, gagern, Martin von Gagern, gagern@ma.tum.de
diff --git a/doc/targets.md b/doc/targets.md
index 00058a4af..e9478aed8 100644
--- a/doc/targets.md
+++ b/doc/targets.md
@@ -18,7 +18,7 @@ The [ANTLR v4 book](http://pragprog.com/book/tpantlr2/the-definitive-antlr-4-ref
 New features generally appear in the Java target and then migrate to the other targets, but these other targets don't always get updated in the same overall tool release. This section tries to identify features added to Java that have not been added to the other targets.
 
 |Feature|Java|C♯|JavaScript|Python2|Python3|Swift|C++|
-|-|-|-|-|-|-|-|-|
+|---|---|---|---|---|---|---|---|
 |Ambiguous tree construction|4.5.1|-|-|-|-|-|-|
  	 	 	 	 	 
  	 	 	 	 	 
diff --git a/runtime/JavaScript/src/antlr4/atn/ATNConfig.js b/runtime/JavaScript/src/antlr4/atn/ATNConfig.js
index 0b13737ed..988729dc7 100644
--- a/runtime/JavaScript/src/antlr4/atn/ATNConfig.js
+++ b/runtime/JavaScript/src/antlr4/atn/ATNConfig.js
@@ -50,7 +50,7 @@ function checkParams(params, isCfg) {
 	} else {
 		var props = {};
 		props.state = params.state || null;
-		props.alt = params.alt || null;
+		props.alt = (params.alt === undefined) ? null : params.alt;
 		props.context = params.context || null;
 		props.semanticContext = params.semanticContext || null;
 		if(isCfg) {
diff --git a/tool/src/org/antlr/v4/codegen/target/Python2Target.java b/tool/src/org/antlr/v4/codegen/target/Python2Target.java
index efa5d2ce9..51ee8689c 100644
--- a/tool/src/org/antlr/v4/codegen/target/Python2Target.java
+++ b/tool/src/org/antlr/v4/codegen/target/Python2Target.java
@@ -61,7 +61,7 @@ public class Python2Target extends Target {
 		"memoryview",
 		"object", "oct", "open", "ord",
 		"pow", "print", "property",
-		"range", "raw_input", "reduce", "reload", "repr", "reversed", "round",
+		"range", "raw_input", "reduce", "reload", "repr", "return", "reversed", "round",
 		"set", "setattr", "slice", "sorted", "staticmethod", "str", "sum", "super",
 		"tuple", "type",
 		"unichr", "unicode",