old_contents: # -*- coding: utf-8 -*-
  
  import arrow
  
  from jinja2 import nodes
  from jinja2.ext import Extension
  
  
  class TimeExtension(Extension):
      tags = set(['now'])
  
      def __init__(self, environment):
          super(TimeExtension, self).__init__(environment)
  
          # add the defaults to the environment
          environment.extend(
              date_format='%Y-%m-%d',
          )
  
      def _now(self, timezone, date_format):
          date_format = date_format or self.environment.date_format
          return arrow.now(timezone).strftime(date_format)
  
      def parse(self, parser):
          lineno = next(parser.stream).lineno
  
          args = [parser.parse_expression()]
  
          if parser.stream.skip_if('comma'):
              args.append(parser.parse_expression())
          else:
              args.append(nodes.Const(None))
  
          call = self.call_method('_now', args, lineno=lineno)
  
          return nodes.Output([call], lineno=lineno)
  
new_contents: # -*- coding: utf-8 -*-
  
  import arrow
  
  from jinja2 import nodes
  from jinja2.ext import Extension
  
  
  class TimeExtension(Extension):
      tags = set(['now'])
  
      def __init__(self, environment):
          super(TimeExtension, self).__init__(environment)
  
          # add the defaults to the environment
          environment.extend(
              datetime_format='%Y-%m-%d',
          )
  
      def _now(self, timezone, datetime_format):
          datetime_format = datetime_format or self.environment.datetime_format
          return arrow.now(timezone).strftime(datetime_format)
  
      def parse(self, parser):
          lineno = next(parser.stream).lineno
  
          args = [parser.parse_expression()]
  
          if parser.stream.skip_if('comma'):
              args.append(parser.parse_expression())
          else:
              args.append(nodes.Const(None))
  
          call = self.call_method('_now', args, lineno=lineno)
  
          return nodes.Output([call], lineno=lineno)
  
subject: Change environment attribute name to datetime_format