Use Python3-style class declaration

Author: maxim-belkin

bin/lesson_check.py

@@ -273,7 +273,7 @@ def create_checker(args, filename, info):
             return cls(args, filename, **info)
     return NotImplemented
 
-class CheckBase(object):
+class CheckBase:
     """Base class for checking Markdown files."""
 
     def __init__(self, args, filename, metadata, metadata_len, text, lines, doc):

bin/util.py

@@ -30,7 +30,7 @@
 REPORTER_NOT_SET = []
 
 
-class Reporter(object):
+class Reporter:
     """Collect and report errors."""
 
     def __init__(self):