diff --git a/argwrap.vim b/argwrap.vim
index a0bd1fd..52d10a3 100644
--- a/argwrap.vim
+++ b/argwrap.vim
@@ -104,9 +104,7 @@ function! argwrap#updateScope(stack, char)
 endfunction
 
 function! argwrap#trimArgument(text)
-    let l:stripped = substitute(a:text, "\\s\\+", "", "")
-    let l:stripped = substitute(l:stripped, "^\\s\\+", "", "")
-    return l:stripped
+    return substitute(a:text, '^\s*\(.\{-}\)\s*$', '\1', '')
 endfunction
 
 function! argwrap#extractArguments(text)
diff --git a/sample.txt b/sample.txt
index 146209f..69d2427 100644
--- a/sample.txt
+++ b/sample.txt
@@ -1,12 +1,16 @@
-    a = Foo("a": 4, "z": 2, [b, z], "hello, world", c)
+    a = Foo(
+        "a": 4,
+        "z": 2,
+        [b, z],
+        "hello, world",
+        c
+    )
+
+Foo(a b, c d)
 
 Foo(a, b)
 
-Foo(
-    a,
-    [b, c],
-    d
-)
+Foo(a, [b, [2, 3] c], d)
 
 Foo(
     a,