New flag for run: --debug, can trace why files aren't being traced.

1 files changed, 2 insertions, 2 deletions

diff --git a/coverage/collector.py b/coverage/collector.py
index 781a0fa6..2abec169 100644
--- a/coverage/collector.py
+++ b/coverage/collector.py
@@ -166,7 +166,7 @@ class Collector(object):
         """Create a collector.
 
         `should_trace` is a function, taking a filename, and returning a
-        canonicalized filename, or False depending on whether the file should
+        canonicalized filename, or None depending on whether the file should
         be traced or not.
 
         If `timid` is true, then a slower simpler trace function will be
@@ -210,7 +210,7 @@ class Collector(object):
 
         # A cache of the results from should_trace, the decision about whether
         # to trace execution in a file. A dict of filename to (filename or
-        # False).
+        # None).
         self.should_trace_cache = {}
 
         # Our active Tracers.