old_contents: class AbstractObject(object):
      
      def __init__(self):
          pass
          
      def send(self, frame, selector_string, arguments, universe):
          # Turn the selector string into a selector
          selector = universe.symbol_for(selector_string)
          invokable = self.get_class(universe).lookup_invokable(selector)
          return invokable.invoke(frame, self, arguments)
  
      def send_does_not_understand(self, frame, selector, arguments, universe):
          # Compute the number of arguments
          number_of_arguments = selector.get_number_of_signature_arguments()
          arguments_array = universe.new_array_with_length(number_of_arguments)
  
          for i in range(0, number_of_arguments):
              arguments_array.set_indexable_field(i, arguments[i])
              
          args = [selector, arguments_array]
          self.send(frame, "doesNotUnderstand:arguments:", args, universe)
  
      def send_unknown_global(self, frame, global_name, universe):
          arguments = [global_name]
          self.send(frame, "unknownGlobal:", arguments, universe)
  
      def send_escaped_block(self, frame, block, universe):
          arguments = [block]
          self.send(frame, "escapedBlock:", arguments, universe)
  
      def get_class(self, universe):
          raise NotImplementedError("Subclasses need to implement get_class(universe).")
  
      def is_invokable(self):
          return False
  
      def __str__(self):
          from som.vm.universe import get_current
          return "a " + self.get_class(get_current()).get_name().get_string()
  
new_contents: class AbstractObject(object):
      
      def __init__(self):
          pass
          
      def send(self, frame, selector_string, arguments, universe):
          # Turn the selector string into a selector
          selector = universe.symbol_for(selector_string)
          invokable = self.get_class(universe).lookup_invokable(selector)
          return invokable.invoke(frame, self, arguments)
  
      def send_does_not_understand(self, frame, selector, arguments, universe):
          # Compute the number of arguments
          number_of_arguments = selector.get_number_of_signature_arguments()
          arguments_array = universe.new_array_with_length(number_of_arguments)
  
          for i in range(0, number_of_arguments):
              arguments_array.set_indexable_field(i, arguments[i])
              
          args = [selector, arguments_array]
          return self.send(frame, "doesNotUnderstand:arguments:", args, universe)
  
      def send_unknown_global(self, frame, global_name, universe):
          arguments = [global_name]
          return self.send(frame, "unknownGlobal:", arguments, universe)
  
      def send_escaped_block(self, frame, block, universe):
          arguments = [block]
          return self.send(frame, "escapedBlock:", arguments, universe)
  
      def get_class(self, universe):
          raise NotImplementedError("Subclasses need to implement get_class(universe).")
  
      def is_invokable(self):
          return False
  
      def __str__(self):
          from som.vm.universe import get_current
          return "a " + self.get_class(get_current()).get_name().get_string()
  
subject: Send methods need to return the result