old_contents: includes = {}
  
  def register_includes(inc):
      global includes
      includes = dict(list(includes.items()) + list(inc.items()))
  
  def include_text():
      global includes
      ret = ''
      for name, function in includes.items():
          ret += function
  
      return ret
  
new_contents: _includes = {}
  
  def register_includes(inc):
      global _includes
      _includes = dict(list(_includes.items()) + list(inc.items()))
  
  def include_text():
      global _includes
      ret = ''
      for name, function in _includes.items():
          ret += function
  
      return ret
  
  def includes():
      global _includes
      print(_includes)
      return _includes
  
subject: add function includes()