X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;f=stopwatch.py;h=fa4f2b52f54998bb029f7e14433e5451abd67812;hb=e8fbbb7306430478dec55d2c963eed116d8330cc;hp=cdd405b558213a9fb7c0ca38eec72ad41ba47a14;hpb=709370b2198e09f1dbe195fe8813602a3125b7f6;p=python_utils.git

diff --git a/stopwatch.py b/stopwatch.py
index cdd405b..fa4f2b5 100644
--- a/stopwatch.py
+++ b/stopwatch.py
@@ -1,7 +1,9 @@
 #!/usr/bin/env python3
 
+"""A simple stopwatch decorator / context for timing things."""
+
 import time
-from typing import Callable
+from typing import Callable, Optional
 
 
 class Timer(object):
@@ -10,7 +12,7 @@ class Timer(object):
 
     e.g.
 
-        with timer.Timer() as t:
+        with stopwatch.Timer() as t:
             do_the_thing()
 
         walltime = t()
@@ -18,8 +20,8 @@ class Timer(object):
     """
 
     def __init__(self) -> None:
-        self.start = None
-        self.end = None
+        self.start = 0.0
+        self.end = 0.0
 
     def __enter__(self) -> Callable[[], float]:
         """Returns a functor that, when called, returns the walltime of the
@@ -29,6 +31,6 @@ class Timer(object):
         self.end = 0.0
         return lambda: self.end - self.start
 
-    def __exit__(self, *args) -> bool:
+    def __exit__(self, *args) -> Optional[bool]:
         self.end = time.perf_counter()
         return None  # don't suppress exceptions