old_contents: """
  Gaia Marketplace helper. Takes packaged manifest as only argument.
  Copy this into the Marketplace app folder (dev/stage/prod whatever), and run.
  Fetches Marketplace package and Etags (e.g., m.f.c/packaged.webapp).
  Downloads application.zip.
  If metadata.json is in path, replaces the appropriate fields.
  """
  import json
  import os
  import requests
  import sys
  
  
  try:
      manifest_url = sys.argv[1]
      if not manifest_url.startswith('http'):
          raise
  except:
      print "Please give a valid manifest (e.g., m.f.c/packaged.webapp)."
      sys.exit(0)
  
  r = requests.get(manifest_url)
  package_path = json.loads(r.content)['package_path']
  etag = r.headers['etag'].replace('"', '')
  
  print "Downloading package"
  r = requests.get(package_path)
  package = r.content
  package_etag = r.headers['etag'].replace('"', '')
  
  f = open('application.zip', 'w')
  f.write(package)
  
  print "Package path: %s" % package_path
  print "Etag: %s" % etag
  print "Package Etag: %s" % package_etag
  
  filename = 'metadata.json'
  try:
      f = open(filename, 'rw')
  except:
      sys.exit(0)
  
  print "Updating metadata.json"
  tmp_filename = 'metadata.json.tmp'
  tmp_f = open(tmp_filename, 'w')
  for line in f:
      if '"etag"' in line:
          line = r'%s%s%s' % (line[0:13], etag, line[-5:])
          line = line.replace(r'\\', r'\\\\')
      elif '"packageEtag"' in line:
          line = r'%s%s%s' % (line[0:20], package_etag, line[-5:])
          line = line.replace(r'\\', r'\\\\')
      tmp_f.write(line)
  tmp_f.close()
  os.rename(tmp_filename, filename)
  
new_contents: """
  Gaia Marketplace helper. Takes packaged manifest as only argument.
  Copy this into the Marketplace app folder (dev/stage/prod whatever), and run.
  Fetches Marketplace package and Etags (e.g., m.f.c/packaged.webapp).
  Downloads application.zip for you.
  If metadata.json is in path, replaces the appropriate fields.
  
  >> python gaia_package.py https://marketplace.firefox.com/packaged.webapp
  
  And you're done!
  """
  import json
  import os
  import requests
  import sys
  
  
  try:
      manifest_url = sys.argv[1]
      if not manifest_url.startswith('http'):
          raise
  except:
      print "Please give a valid manifest (e.g., m.f.c/packaged.webapp)."
      sys.exit(0)
  
  r = requests.get(manifest_url)
  package_path = json.loads(r.content)['package_path']
  etag = r.headers['etag'].replace('"', '')
  
  print "Downloading package"
  r = requests.get(package_path)
  package = r.content
  package_etag = r.headers['etag'].replace('"', '')
  
  f = open('application.zip', 'w')
  f.write(package)
  
  print "Package path: %s" % package_path
  print "Etag: %s" % etag
  print "Package Etag: %s" % package_etag
  
  filename = 'metadata.json'
  try:
      f = open(filename, 'rw')
  except:
      sys.exit(0)
  
  print "Updating metadata.json"
  tmp_filename = 'metadata.json.tmp'
  tmp_f = open(tmp_filename, 'w')
  for line in f:
      if '"etag"' in line:
          line = r'%s%s%s' % (line[0:13], etag, line[-5:])
          line = line.replace(r'\\', r'\\\\')
      elif '"packageEtag"' in line:
          line = r'%s%s%s' % (line[0:20], package_etag, line[-5:])
          line = line.replace(r'\\', r'\\\\')
      tmp_f.write(line)
  tmp_f.close()
  os.rename(tmp_filename, filename)
  
subject: add some more comments to gaia_package script