diff --git a/noid.py b/noid.py
index df4433e..6277354 100644
--- a/noid.py
+++ b/noid.py
@@ -17,6 +17,7 @@ class Counter():
 @dataclass
 class Minter(Persistent):
     legalstring: ClassVar[str] = "0123456789bcdfghjkmnpqrstvwxz"
+    xdig: tuple[str] = tuple(legalstring)
     alphacount: ClassVar[int] = len(legalstring)
     digitcount: ClassVar[int] = 10
     
@@ -138,7 +139,6 @@ class Minter(Persistent):
         # 8. return s
         s = ""
         varwidth = 0
-        xdig = list(self.legalstring)
         rmask = list(self.template)
         rmask.reverse()
         while num != 0 or not varwidth:
@@ -164,7 +164,7 @@ class Minter(Persistent):
                         continue
             remainder = num % div
             num = int(num / div)
-            s = xdig[remainder] + s
+            s = self.xdig[remainder] + s
         if self.template[-1] == "k":
             s += "+"
         return s