old_contents: import sys
  import time
  import logging
  from optparse import make_option
  from django.core.management.base import BaseCommand, CommandError
  from avocado.management.base import DataFieldCommand
  
  log = logging.getLogger(__name__)
  
  
  _help = """\
  Pre-caches data produced by various DataField methods that are data dependent.
  
  Pass `--flush` to explicitly flush any existing cache for each property.
  """
  
  CACHED_METHODS = ('size', 'values', 'labels', 'codes')
  
  class Command(DataFieldCommand):
      __doc__ = help = _help
  
      option_list = BaseCommand.option_list + (
          make_option('--flush', action='store_true',
              help='Flushes existing cache for each cached property.'),
  
          make_option('--method', action='append', dest='methods',
              default=CACHED_METHODS,
              help='Select which methods to pre-cache. Choices: {0}'.format(', '.join(CACHED_METHODS))),
      )
  
      def _progress(self):
          sys.stdout.write('.')
          sys.stdout.flush()
  
      def handle_fields(self, fields, **options):
          flush = options.get('flush')
          methods = options.get('methods')
  
          for method in methods:
              if method not in CACHED_METHODS:
                  raise CommandError('Invalid method {0}. Choices are {1}'.format(method, ', '.join(CACHED_METHODS)))
  
          fields = fields.filter(enumerable=True)
  
          count = 0
          for f in fields:
              t0 = time.time()
              for method in methods:
                  func = getattr(f, method)
                  if flush:
                      func.flush()
                  func()
                  self._progress()
              count += 1
              log.debug('{0} cache set took {1:,} seconds'.format(f, time.time() - t0))
  
          print(u'{0} DataFields have been updated'.format(count))
  
new_contents: import sys
  import time
  import logging
  from optparse import make_option
  from django.core.management.base import BaseCommand, CommandError
  from avocado.management.base import DataFieldCommand
  
  log = logging.getLogger(__name__)
  
  
  _help = """\
  Pre-caches data produced by various DataField methods that are data dependent.
  
  Pass `--flush` to explicitly flush any existing cache for each property.
  """
  
  CACHED_METHODS = ('size', 'values', 'labels', 'codes')
  
  class Command(DataFieldCommand):
      __doc__ = help = _help
  
      option_list = BaseCommand.option_list + (
          make_option('--flush', action='store_true',
              help='Flushes existing cache for each cached property.'),
  
          make_option('--method', action='append', dest='methods',
              default=CACHED_METHODS,
              help='Select which methods to pre-cache. Choices: {0}'.format(', '.join(CACHED_METHODS))),
      )
  
      def _progress(self):
          sys.stdout.write('.')
          sys.stdout.flush()
  
      def handle_fields(self, fields, **options):
          flush = options.get('flush')
          methods = options.get('methods')
  
          for method in methods:
              if method not in CACHED_METHODS:
                  raise CommandError('Invalid method {0}. Choices are {1}'.format(method, ', '.join(CACHED_METHODS)))
  
          fields = fields.filter(enumerable=True)
  
          count = 0
          for f in fields:
              t0 = time.time()
              for method in methods:
                  func = getattr(f, method)
                  if flush:
                      func.flush()
                  func()
                  self._progress()
              count += 1
              log.debug('{0} cache set took {1} seconds'.format(f, time.time() - t0))
  
          print(u'{0} DataFields have been updated'.format(count))
  
subject: Remove format option to maintain python 2.6 compatibility