Exception Chaining missing method for suppressing context

Lib/traceback.py

 """Extract, format and print information about Python stack traces."""
 
 import linecache
 import sys
 
 __all__ = ['extract_stack', 'extract_tb', 'format_exception',
            'format_exception_only', 'format_list', 'format_stack',
            'format_tb', 'print_exc', 'format_exc', 'print_exception',
            'print_last', 'print_stack', 'print_tb']
 
@@ skipping 102 matching lines @@
 _context_message = (
     "\nDuring handling of the above exception, "
     "another exception occurred:\n")
 
 def _iter_chain(exc, custom_tb=None, seen=None):
     if seen is None:
         seen = set()
     seen.add(exc)
     its = []
     cause = exc.__cause__
-    if cause is not None and cause not in seen:
-        its.append(_iter_chain(cause, None, seen))
-        its.append([(_cause_message, None)])
-    else:
+    if cause is Ellipsis:
         context = exc.__context__
         if context is not None and context not in seen:
             its.append(_iter_chain(context, None, seen))
             its.append([(_context_message, None)])
+    elif cause is not None and cause not in seen:
+        its.append(_iter_chain(cause, False, seen))
+        its.append([(_cause_message, None)])
     its.append([(exc, custom_tb or exc.__traceback__)])
     # itertools.chain is in an extension module and may be unavailable
     for it in its:
         for x in it:
             yield x
 
 
 def print_exception(etype, value, tb, limit=None, file=None, chain=True):
     """Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
 
@@ skipping 190 matching lines @@
         name = co.co_name
         linecache.checkcache(filename)
         line = linecache.getline(filename, lineno, f.f_globals)
         if line: line = line.strip()
         else: line = None
         list.append((filename, lineno, name, line))
         f = f.f_back
         n = n+1
     list.reverse()
     return list