add license and some documentation

yadenon.py

@@ -1,13 +1,48 @@
 #!/usr/bin/env python
 
+__author__ = 'John-Mark Gurney'
+__copyright__ = 'Copyright 2017 John-Mark Gurney.  All rights reserved.'
+__license__ = '2-clause BSD license'
+
+# Copyright 2017, John-Mark Gurney
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice, this
+#    list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# The views and conclusions contained in the software and documentation are those
+# of the authors and should not be interpreted as representing official policies,
+# either expressed or implied, of the Project.
+
 import mock
 import serial
 import unittest
 import threading
 import time
 
+__all__ = [ 'DenonAVR' ]
+
 class DenonAVR(object):
 	def __init__(self, serdev):
+		'''Specify the serial device connected to the Denon AVR.'''
+
 		self._ser = serial.serial_for_url(serdev, baudrate=9600,
 		    timeout=.5)
 		self._power = None
@@ -192,7 +227,8 @@ class DenonAVR(object):
 				return event
 
 	def update(self):
-		'''Update the status of the AVR.'''
+		'''Update the status of the AVR.  This ensures that the
+		state of the object matches the amp.'''
 
 		self._sendcmd('PW', '?')
 		self._sendcmd('MV', '?')