new_contents: """A class definition for the clipboard and some actors."""
  from .action import Interactive
  
  class InteractionStack:
      """Stack-like datastructure for storing and handling interactive actions."""
      storage = []
  
      @property
      def isempty(self):
          return len(self.storage) == 0
  
      def push(self, interaction):
          """Push interaction on the stack."""
          assert isinstance(interaction, Interactive)
          self.storage.append(interaction)
  
      def peek(self, offset=0):
          """
          Return the interactoin with offset relative to the top of the stack.
          """
          return self.storage[-1 - offset]
  
      def backtrack(self):
          """Remove current interaction and return parent."""
          self.storage.pop()
          if not self.isempty:
              return self.storage[-1]
  
  
subject: add file now :)