Use string.ascii_lowercase instead of string.lowercase when uniquifying.
@@ -92,7 +92,7 @@ class VersionSlugField(models.CharField):
uniquifying_suffix(26) == '_ba'
uniquifying_suffix(52) == '_ca'
"""
- alphabet = string.lowercase
+ alphabet = string.ascii_lowercase
length = len(alphabet)
if iteration == 0:
power = 0
