Prefer '\0' to None or an empty string for single characters.

poezio/theming.py

@@ -400,7 +400,7 @@ def read_tuple(_str):
     Read a tuple dumped with dump_tumple
     """
     attrs = _str.split(',')
-    char = attrs[2] if len(attrs) > 2 else None
+    char = attrs[2] if len(attrs) > 2 else '\0'
     return (int(attrs[0]), int(attrs[1])), char
 
 def to_curses_attr(color_tuple):

poezio/windows/funcs.py

@@ -35,7 +35,7 @@ def parse_attrs(text, previous=None):
         if next_attr_char + 1 < len(text):
             attr_char = text[next_attr_char+1].lower()
         else:
-            attr_char = str()
+            attr_char = '\0'
         if attr_char == 'o':
             attrs = []
         elif attr_char == 'u':