diff --git a/letsencrypt-nginx/letsencrypt_nginx/nginxparser.py b/letsencrypt-nginx/letsencrypt_nginx/nginxparser.py
index 2926a43d0..cef0756d7 100644
--- a/letsencrypt-nginx/letsencrypt_nginx/nginxparser.py
+++ b/letsencrypt-nginx/letsencrypt_nginx/nginxparser.py
@@ -84,7 +84,7 @@ class RawNginxDumper(object):
                     else:
                         yield spacer * current_indent + key + spacer + values + ';'
 
-    def as_string(self):
+    def __str__(self):
         """Return the parsed block as a string."""
         return '\n'.join(self) + '\n'
 
@@ -122,7 +122,7 @@ def dumps(blocks, indentation=4):
     :rtype: str
 
     """
-    return RawNginxDumper(blocks, indentation).as_string()
+    return str(RawNginxDumper(blocks, indentation))
 
 
 def dump(blocks, _file, indentation=4):