Apply suggestion to soitool/coder.py

soitool/coder.py

@@ -70,7 +70,7 @@ def get_code_set(count, code_length, mode="ascii", space_interval=0):
     mode : string
         'ascii' for letters (default), 'digits' for digits and 'combo'
         for combination of letters and digits.
-    space_interval : int or 0
+    space_interval : int
         Spaces will be inserted to code each interval if not 0, by default 0.
 
     Return