logging: Use default formatter if none set.

Signed-off-by: Colin Nolan <cn580@alumni.york.ac.uk>

python-stdlib/logging/logging.py

@@ -53,7 +53,11 @@ class Handler:
         self.formatter = formatter
 
     def format(self, record):
-        return self.formatter.format(record)
+        if self.formatter:
+            fmt = self.formatter
+        else:
+            fmt = _defaultFormatter
+        return fmt.format(record)
 
 
 class StreamHandler(Handler):
@@ -106,6 +110,12 @@ class Formatter:
         }
 
 
+#
+#   The default formatter to use when no other is specified
+#
+_defaultFormatter = Formatter()
+
+
 class Logger:
     def __init__(self, name, level=NOTSET):
         self.name = name