Use repr= now that we have it

Author: JelleZijlstra

Lib/configparser.py

@@ -372,11 +372,6 @@ def __init__(self):
         Error.__init__(self, "Support for UNNAMED_SECTION is disabled.")
 
 
-class _UnnamedSection:
-
-    def __repr__(self):
-        return "<UNNAMED_SECTION>"
-
 class InvalidWriteError(Error):
     """Raised when attempting to write data that the parser would read back differently.
     ex: writing a key which begins with the section header pattern would read back as a
@@ -386,7 +381,7 @@ def __init__(self, msg=''):
         Error.__init__(self, msg)
 
 
-UNNAMED_SECTION = _UnnamedSection()
+UNNAMED_SECTION = sentinel("UNNAMED_SECTION", repr="<UNNAMED_SECTION>")
 
 
 # Used in parser getters to indicate the default behaviour when a specific

Lib/dataclasses.py

@@ -172,10 +172,7 @@ class FrozenInstanceError(AttributeError): pass
 # A sentinel object for default values to signal that a default
 # factory will be used.  This is given a nice repr() which will appear
 # in the function signature of dataclasses' constructors.
-class _HAS_DEFAULT_FACTORY_CLASS:
-    def __repr__(self):
-        return '<factory>'
-_HAS_DEFAULT_FACTORY = _HAS_DEFAULT_FACTORY_CLASS()
+_HAS_DEFAULT_FACTORY = sentinel("_HAS_DEFAULT_FACTORY", repr="<factory>")
 
 # A sentinel object to detect if a parameter is supplied or not.
 MISSING = sentinel("MISSING")

Lib/traceback.py

@@ -136,11 +136,7 @@ def extract_tb(tb, limit=None):
     "another exception occurred:\n\n")
 
 
-class _Sentinel:
-    def __repr__(self):
-        return "<implicit>"
-
-_sentinel = _Sentinel()
+_sentinel = sentinel("_sentinel", repr="<implicit>")
 
 def _parse_value_tb(exc, value, tb):
     if (value is _sentinel) != (tb is _sentinel):