diff --git a/argwrap.vim b/argwrap.vim
index b017302..3b45a19 100644
--- a/argwrap.vim
+++ b/argwrap.vim
@@ -96,10 +96,17 @@ function! argwrap#extractContainer(range)
 endfunction
 
 function! argwrap#wrapContainer(range, container, arguments)
-    let l:line = a:range.lineStart
+    let l:argCount = len(a:arguments)
+    let l:line     = a:range.lineStart
+
     call setline(l:line, a:container.prefix)
-    for l:argument in a:arguments
-        call append(l:line, l:argument . ",")
+    for l:index in range(l:argCount)
+        let l:text = a:arguments[l:index]
+        if l:index < l:argCount - 1
+            let l:text .= ","
+        endif
+
+        call append(l:line, l:text)
         let l:line += 1
         exec printf("%s>", l:line)
     endfor
diff --git a/sample.txt b/sample.txt
index faba30b..72271f2 100644
--- a/sample.txt
+++ b/sample.txt
@@ -1,16 +1,15 @@
-a = Foo(a, [b, z], "hello, world", c, )
-
-Foo(a, b)
+a = Foo(a, [b, z], "hello, world", c)
 
 Foo(
     a,
-    [b, c],
-    d
+    b
 )
 
+Foo(a, [b, c], d)
+
 Foo(
-    a
-    [b, "c"]
+    a,
+    [b, "c"],
     d
 )
 
@@ -20,11 +19,4 @@ Foo(
     d
 )
 
-Foo(
-    a,
-    [
-        b,
-        c
-    ],
-    d
-)
+Foo(a, [b, c], d)