old_contents: """Tokenizer"""
  
  class Tokenizer(object):
      """Tokenizer class.
  
      Parameters:
          return_set (boolean): flag to indicate whether to return a set of
                                tokens. (defaults to False) 
      """
      def __init__(self, return_set=False):
          self.return_set = return_set
  
      def get_return_set(self):
          """
          Get the return_set flag
  
          Returns:
              return_set (boolean)
          """
          return self.return_set
  
      def set_return_set(self, return_set):
          """
          Set the return_set flag
  
          Args:
              return_set (boolean): flag to indicate whether to return a set of tokens. 
          """
          self.return_set = return_set
          return True
  
new_contents: """Tokenizer"""
  
  class Tokenizer(object):
      """Tokenizer class.
  
      Parameters:
          return_set (boolean): an attribute which is a flag to indicate whether to return a set of
                                tokens instead of a bag of tokens (defaults to False).
      """
      def __init__(self, return_set=False):
          self.return_set = return_set
  
      def get_return_set(self):
          """Get the return_set flag.
  
          Returns:
              The boolean value of the return_set attribute.
          """
          return self.return_set
  
      def set_return_set(self, return_set):
          """Set the return_set flag.
  
          Args:
              return_set (boolean): flag to indicate whether to return a set of tokens or a bag of tokens. 
          """
          self.return_set = return_set
          return True
  
subject: Update tokenizer.py