Fixed length comparison bug

Author: seanlaw

versions.py

@@ -479,7 +479,7 @@ def get_all_min_versions(MIN_PYTHON):
     elif args.mode == "max":
         get_all_max_versions()
     elif args.mode == "range":
-        if len(args.python_version) <= 2:
+        if len(args.python_version) != 2:
             raise IndexError("Please provide both a start and stop version")
         start = args.python_version[0]
         stop = args.python_version[1]