--- a/configmix/config.py	Fri Dec 17 11:09:14 2021 +0100
+++ b/configmix/config.py	Fri Dec 17 11:42:47 2021 +0100
@@ -736,25 +736,25 @@
         """
         if klass._QUOTE not in s:
             return s
-        res = []
         parts = s.split(klass._QUOTE)
-        res.append(parts[0])
+        res = [parts[0]]
+        res_append = res.append
         for p in parts[1:]:
             if p.startswith(u(b'x')):
                 if len(p) < 3:
                     raise ValueError("quote syntax: length too small")
-                res.append(uchr(int(p[1:3], 16)))
-                res.append(p[3:])
+                res_append(uchr(int(p[1:3], 16)))
+                res_append(p[3:])
             elif p.startswith(u(b'u')):
                 if len(p) < 5:
                     raise ValueError("quote syntax: length too small")
-                res.append(uchr(int(p[1:5], 16)))
-                res.append(p[5:])
+                res_append(uchr(int(p[1:5], 16)))
+                res_append(p[5:])
             elif p.startswith(u(b'U')):
                 if len(p) < 9:
                     raise ValueError("quote syntax: length too small")
-                res.append(uchr(int(p[1:9], 16)))
-                res.append(p[9:])
+                res_append(uchr(int(p[1:9], 16)))
+                res_append(p[9:])
             else:
                 raise ValueError("unknown quote syntax string: {}".format(s))
         return ''.join(res)