diff --git a/Lib/sched.py b/Lib/sched.py
index 60b0a1bacfd..147977cfe9b 100644
--- a/Lib/sched.py
+++ b/Lib/sched.py
@@ -1,99 +1,104 @@
-# Module sched -- a generally useful event scheduler class
+"""Module sched -- a generally useful event scheduler class
 
-# Each instance of this class manages its own queue.
-# No multi-threading is implied; you are supposed to hack that
-# yourself, or use a single instance per application.
-#
-# Each instance is parametrized with two functions, one that is
-# supposed to return the current time, one that is supposed to
-# implement a delay.  You can implement real-time scheduling by
-# substituting time and sleep from built-in module time, or you can
-# implement simulated time by writing your own functions.  This can
-# also be used to integrate scheduling with STDWIN events; the delay
-# function is allowed to modify the queue.  Time can be expressed as
-# integers or floating point numbers, as long as it is consistent.
+Each instance of this class manages its own queue.
+No multi-threading is implied; you are supposed to hack that
+yourself, or use a single instance per application.
 
-# Events are specified by tuples (time, priority, action, argument).
-# As in UNIX, lower priority numbers mean higher priority; in this
-# way the queue can be maintained fully sorted.  Execution of the
-# event means calling the action function, passing it the argument.
-# Remember that in Python, multiple function arguments can be packed
-# in a tuple.   The action function may be an instance method so it
-# has another way to reference private data (besides global variables).
-# Parameterless functions or methods cannot be used, however.
+Each instance is parametrized with two functions, one that is
+supposed to return the current time, one that is supposed to
+implement a delay.  You can implement real-time scheduling by
+substituting time and sleep from built-in module time, or you can
+implement simulated time by writing your own functions.  This can
+also be used to integrate scheduling with STDWIN events; the delay
+function is allowed to modify the queue.  Time can be expressed as
+integers or floating point numbers, as long as it is consistent.
+
+Events are specified by tuples (time, priority, action, argument).
+As in UNIX, lower priority numbers mean higher priority; in this
+way the queue can be maintained fully sorted.  Execution of the
+event means calling the action function, passing it the argument.
+Remember that in Python, multiple function arguments can be packed
+in a tuple.   The action function may be an instance method so it
+has another way to reference private data (besides global variables).
+Parameterless functions or methods cannot be used, however.
+"""
 
 # XXX The timefunc and delayfunc should have been defined as methods
 # XXX so you can define new kinds of schedulers using subclassing
 # XXX instead of having to define a module or class just to hold
-# XXX the global state of your particular time and delay functtions.
+# XXX the global state of your particular time and delay functions.
 
 import bisect
 
 class scheduler:
-	#
-	# Initialize a new instance, passing the time and delay functions
-	#
-	def __init__(self, timefunc, delayfunc):
-		self.queue = []
-		self.timefunc = timefunc
-		self.delayfunc = delayfunc
-	#
-	# Enter a new event in the queue at an absolute time.
-	# Returns an ID for the event which can be used
-	# to remove it, if necessary.
-	#
-	def enterabs(self, time, priority, action, argument):
-		event = time, priority, action, argument
-		bisect.insort(self.queue, event)
-		return event # The ID
-	#
-	# A variant that specifies the time as a relative time.
-	# This is actually the more commonly used interface.
-	#
-	def enter(self, delay, priority, action, argument):
-		time = self.timefunc() + delay
-		return self.enterabs(time, priority, action, argument)
-	#
-	# Remove an event from the queue.
-	# This must be presented the ID as returned by enter().
-	# If the event is not in the queue, this raises RuntimeError.
-	#
-	def cancel(self, event):
-		self.queue.remove(event)
-	#
-	# Check whether the queue is empty.
-	#
-	def empty(self):
-		return len(self.queue) == 0
-	#
-	# Run: execute events until the queue is empty.
-	#
-	# When there is a positive delay until the first event, the
-	# delay function is called and the event is left in the queue;
-	# otherwise, the event is removed from the queue and executed
-	# (its action function is called, passing it the argument).
-	# If the delay function returns prematurely, it is simply
-	# restarted.
-	#
-	# It is legal for both the delay function and the action
-	# function to to modify the queue or to raise an exception;
-	# exceptions are not caught but the scheduler's state
-	# remains well-defined so run() may be called again.
-	#
-	# A questionably hack is added to allow other threads to run:
-	# just after an event is executed, a delay of 0 is executed,
-	# to avoid monopolizing the CPU when other threads are also
-	# runnable.
-	#
-	def run(self):
-		q = self.queue
-		while q:
-			time, priority, action, argument = q[0]
-			now = self.timefunc()
-			if now < time:
-				self.delayfunc(time - now)
-			else:
-				del q[0]
-				void = apply(action, argument)
-				self.delayfunc(0) # Let other threads run
-	#
+    def __init__(self, timefunc, delayfunc):
+        """Initialize a new instance, passing the time and delay
+        functions"""
+        self.queue = []
+        self.timefunc = timefunc
+        self.delayfunc = delayfunc
+
+    def enterabs(self, time, priority, action, argument):
+        """Enter a new event in the queue at an absolute time.
+
+	Returns an ID for the event which can be used to remove it,
+	if necessary.
+
+	"""
+        event = time, priority, action, argument
+        bisect.insort(self.queue, event)
+        return event # The ID
+
+    def enter(self, delay, priority, action, argument):
+        """A variant that specifies the time as a relative time.
+
+	This is actually the more commonly used interface.
+
+	"""
+        time = self.timefunc() + delay
+        return self.enterabs(time, priority, action, argument)
+
+    def cancel(self, event):
+        """Remove an event from the queue.
+
+	This must be presented the ID as returned by enter().
+	If the event is not in the queue, this raises RuntimeError.
+
+	"""
+        self.queue.remove(event)
+
+    def empty(self):
+        """Check whether the queue is empty."""
+        return len(self.queue) == 0
+
+    def run(self):
+        """Execute events until the queue is empty.
+   
+	When there is a positive delay until the first event, the
+	delay function is called and the event is left in the queue;
+	otherwise, the event is removed from the queue and executed
+	(its action function is called, passing it the argument).  If
+	the delay function returns prematurely, it is simply
+	restarted.
+
+	It is legal for both the delay function and the action
+	function to to modify the queue or to raise an exception;
+	exceptions are not caught but the scheduler's state remains
+	well-defined so run() may be called again.
+
+	A questionably hack is added to allow other threads to run:
+	just after an event is executed, a delay of 0 is executed, to
+	avoid monopolizing the CPU when other threads are also
+	runnable.
+
+	"""
+        q = self.queue
+        while q:
+            time, priority, action, argument = q[0]
+            now = self.timefunc()
+            if now < time:
+                self.delayfunc(time - now)
+            else:
+                del q[0]
+                void = apply(action, argument)
+                self.delayfunc(0)   # Let other threads run