powernap parses /proc/interrupts incorrectly

Running powernap 2.21-0ubuntu-1 on Ubuntu-15.10. Kernel 4.2.0-10

Powernap tries to parse /proc/interrupts to discover IRQs for the keyboard and mouse. However, the format of this file seems to have changed in recent kernels, and this causes the following error and backtrace in /var/log/powernap.err

Traceback (most recent call last):
  File "/usr/sbin/powernapd", line 342, in <module>
    MONITORS = powernap.get_monitors()
  File "/usr/lib/python2.7/dist-packages/powernap/powernap.py", line 183, in get_monitors
    p = ConsoleMonitor.ConsoleMonitor(config)
  File "/usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py", line 53, in __init__
    self._time, self._irqs = get_console_activity()
  File "/usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py", line 28, in get_console_activity
    irqs = get_interrupts()
  File "/usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py", line 42, in get_interrupts
    interrupts += int(i)
ValueError: invalid literal for int() with base 10: 'IR-IO-APIC'

On another machine, running linux 3.13, lines in /proc/interrupts looks like this:

           CPU0 CPU1
  0: 251660783 0 IO-APIC-edge timer
  8: 1 0 IO-APIC-edge rtc0
  9: 3 0 IO-APIC-fasteoi acpi

On 4.2 (and maybe earlier?), there is another column on the right hand side, e.g.

           CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
  0: 16 0 0 0 0 0 0 0 IR-IO-APIC 2-edge timer
  1: 2 0 0 0 0 0 0 0 IR-IO-APIC 1-edge i8042

get_interrupts() in /usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py searches this file for i8042/keyboard/mouse. When it finds a valid line, it drops the first and two last columns. The remaining columns are assumed to be IRQ numbers and parsed as integers. Since there is an extra column, 'IR-IO-APIC' gets read and it crashes when trying to parse this as an int.

A simple fix would be:

--- /tmp/ConsoleMonitor.py 2015-09-20 21:39:51.862439624 +0100
+++ /usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py 2015-09-20 21:40:08.922204486 +0100
@@ -38,6 +38,7 @@
         if source == "i8042" or source == "keyboard" or source == "mouse":
             items.pop(0)
             items.pop()
+ items.pop()
             for i in items:
                 interrupts += int(i)
     f.close()

Of course, this isn't a great fix since it won't work properly on older kernels. Perhaps something like this instead:

--- /tmp/ConsoleMonitor.py 2015-09-20 21:39:51.862439624 +0100
+++ /usr/lib/python2.7/dist-packages/powernap/monitors/ConsoleMonitor.py 2015-09-20 21:50:38.785528258 +0100
@@ -39,7 +39,10 @@
             items.pop(0)
             items.pop()
             for i in items:
- interrupts += int(i)
+ try:
+ interrupts += int(i)
+ except:
+ pass
     f.close()
     return interrupts

Both seem to work on my system. However, I hardly know any python, so there's probably a much nicer way to fix this.