diff --git a/autoload/airline/extensions/hunks.vim b/autoload/airline/extensions/hunks.vim
index 2a89f789..2b70f1ba 100644
--- a/autoload/airline/extensions/hunks.vim
+++ b/autoload/airline/extensions/hunks.vim
@@ -1,21 +1,15 @@
 " MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: et ts=2 sts=2 sw=2
 
-function! s:check_defined(variable, default)
-  if !exists(a:variable)
-    let {a:variable} = a:default
-  endif
-endfunction
-
-call s:check_defined('g:airline#extensions#hunks#non_zero_only', 0)
-call s:check_defined('g:airline#extensions#hunks#hunk_symbols', ['+', '~', '-'])
+let s:non_zero_only = get(g:, 'airline#extensions#hunks#non_zero_only', 0)
+let s:hunk_symbols = get(g:, 'airline#extensions#hunks#hunk_symbols', ['+', '~', '-'])
 
 function! airline#extensions#hunks#get_hunks()
   let hunks = GitGutterGetHunkSummary()
   let string = ''
   for i in [0, 1, 2]
-    if g:airline#extensions#hunks#non_zero_only == 0 || hunks[i] > 0
-      let string .= printf('%s%s ', g:airline#extensions#hunks#hunk_symbols[i], hunks[i])
+    if s:non_zero_only == 0 || hunks[i] > 0
+      let string .= printf('%s%s ', s:hunk_symbols[i], hunks[i])
     endif
   endfor
   return string