old_contents: import json
  import ijson
  
  class TimeSeriesJSON:
  
      def __init__(self, f=None, fn=None, tag='item'):
          """
          :param f: file object (_io.TextIOWrapper)
          :param fn: file name as a string
          :param tag: tag for dividing json items
              default value is 'item' because this value is default in ijson
          """
          if f is not None:
              self.__type = 'file'
              self.__file = f
          elif fn is not None:
              self.__type = 'file_name'
              self.__file_name = fn
              self.__file = open(fn)
  
          self.__items = self.parse_json_items(tag)
  
      def parse_json_items(self, tag, limit=0):
          self.__items = []
          self.__file.seek(0)
          cnt = 0
  
          objs = ijson.items(self.__file, tag)
          for obj in objs:
              item = json.dumps(obj, \
                                sort_keys=True, \
                                indent=4, \
                                ensure_ascii=True)
              self.__items.append(item)
              cnt += 1
              if limit != 0 and cnt >= limit:
                  break
  
          return self.__items
  
new_contents: import json
  import ijson
  
  
  class TimeSeriesJSON:
  
      def __init__(self, f=None, fn=None, tag='item'):
          """
          :param f: file object (_io.TextIOWrapper)
          :param fn: file name as a string
          :param tag: tag for dividing json items
              default value is 'item' because this value is default in ijson
          """
          if f is not None:
              self.__type = 'file'
              self.__file = f
          elif fn is not None:
              self.__type = 'file_name'
              self.__file_name = fn
              self.__file = open(fn)
  
          self.__items = self.parse_json_items(tag)
  
      def parse_json_items(self, tag, limit=0):
          self.__items = []
          self.__file.seek(0)
          cnt = 0
  
          objs = ijson.items(self.__file, tag)
          for obj in objs:
              item = json.dumps(obj, \
                                sort_keys=True, \
                                indent=4, \
                                ensure_ascii=True)
              self.__items.append(item)
              cnt += 1
              if limit != 0 and cnt >= limit:
                  break
  
          return self.__items
  
subject: Make whitespaces before TimeSeriesJSON for PEP8