Linux / Mac battery level in zsh right side prompt

.zshrc

...

if [[ -r $HOME/.zshstuff/batterylevel.py ]]; then
    RPROMPT="$RPROMPT $(python $HOME/.zshstuff/batterylevel.py)"
fi

# Bonus! Indicator of stopped (^Z'd) jobs

function stopped_jobs(){
  if [[ "$(jobs)" =~ "suspended" ]]; then
    echo "%{$fg_bold[red]%}⌚ " # this is supposed to be a clock symbol
  fi
}

RPROMPT="\$(stopped_jobs)$RPROMPT"

batterylevel.py

#!/usr/bin/env python
# coding=UTF-8

import math, subprocess, sys

if sys.platform == 'linux' or sys.platform == 'linux2':
  try:
    b_max = float(file('/sys/class/power_supply/BAT0/energy_full').read().strip())
    b_cur = float(file('/sys/class/power_supply/BAT0/energy_now').read().strip())
  except IOError:
    sys.exit(0)
elif sys.platform == 'darwin':
  p = subprocess.Popen(["ioreg", "-rc", "AppleSmartBattery"], stdout=subprocess.PIPE)
  output = p.communicate()[0]

  o_max = [l for l in output.splitlines() if 'MaxCapacity' in l][0]
  o_cur = [l for l in output.splitlines() if 'CurrentCapacity' in l][0]

  b_max = float(o_max.rpartition('=')[-1].strip())
  b_cur = float(o_cur.rpartition('=')[-1].strip())
else:
  sys.exit(0)

charge = b_cur / b_max
charge_threshold = int(math.ceil(10 * charge))

# Output

total_slots, slots = 10, []
filled = int(math.ceil(charge_threshold * (total_slots / 10.0))) * u'▸'
empty = (total_slots - len(filled)) * u'▹'

out = (filled + empty).encode('utf-8')
import sys

# these are supposed to be right-facing filled triangles...
color_green = '%{%}'
color_yellow = '%{%}'
color_red = '%{%}'
color_reset = '%{%}'
color_out = (
    color_green if len(filled) > 6
    else color_yellow if len(filled) > 4
    else color_red
)

out = color_out + out + color_reset
sys.stdout.write(out)