docs: def copy(app, need, needs, option, need_id=None):
      """
      Copies the value of one need option to another
  
      .. code-block:: jinja
  
          .. req:: copy-example
             :id: copy_1
             :tags: tag_1, tag_2, tag_3
             :status: open
  
          .. spec:: copy-example implementation
             :id: copy_2
             :status: [[copy("status", "copy_1")]]
             :links: copy_1
             :comment: [[copy("id")]]
  
             Copies status of ``copy_1`` to own status.
             Sets also a comment, which copies the id of own need.
  
          .. test:: test of specification and requirement
             :id: copy_3
             :links: copy_2; [[copy('links', 'copy_2')]]
             :tags: [[copy('tags', 'copy_1')]]
  
             Set own link to ``copy_2`` and also copies all links from it.
  
             Also copies all tags from copy_1.
  
      .. req:: copy-example
         :id: copy_1
         :tags: tag_1, tag_2, tag_3
         :status: open
  
      .. spec:: copy-example implementation
         :id: copy_2
         :status: [[copy("status", "copy_1")]]
         :links: copy_1
         :comment: [[copy("id")]]
  
         Copies status of ``copy_1`` to own status.
         Sets also a comment, which copies the id of own need.
  
      .. test:: test of specification and requirement
         :id: copy_3
         :links: copy_2; [[copy('links', 'copy_2')]]
         :tags: [[copy('tags', 'copy_1')]]
  
         Set own link to ``copy_2`` and also copies all links from it.
  
         Also copies all tags from copy_1.
  
      :param option: Name of the option to copy
      :param need_id: id of the need, which contains the source option. If None, current need is taken
      :return: string of copied need option
      """
      if need_id is not None:
          need = needs[need_id]
  
      return need[option]