PicklingError("Can't pickle <class 'store.Poem'>: it's not the same object as store.Poem",)

Full traceback:
  File "renpy/common/00gamemenu.rpy", line 173, in script
    $ ui.interact()
  File "/usr/local/apps/ddlc/cb/renpy/ast.py", line 814, in execute
    renpy.python.py_exec_bytecode(self.code.bytecode, self.hide, store=self.store)
  File "/usr/local/apps/ddlc/cb/renpy/python.py", line 1719, in py_exec_bytecode
    exec bytecode in globals, locals
  File "renpy/common/00gamemenu.rpy", line 173, in <module>
    $ ui.interact()
  File "/usr/local/apps/ddlc/cb/renpy/ui.py", line 285, in interact
    rv = renpy.game.interface.interact(roll_forward=roll_forward, **kwargs)
  File "/usr/local/apps/ddlc/cb/renpy/display/core.py", line 2526, in interact
    repeat, rv = self.interact_core(preloads=preloads, trans_pause=trans_pause, **kwargs)
  File "/usr/local/apps/ddlc/cb/renpy/display/core.py", line 3204, in interact_core
    rv = root_widget.event(ev, x, y, 0)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/transition.py", line 45, in event
    return self.new_widget.event(ev, x, y, st)  # E1101
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/screen.py", line 651, in event
    rv = self.child.event(ev, x, y, st)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 232, in event
    rv = d.event(ev, x - xo, y - yo, st)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 232, in event
    rv = d.event(ev, x - xo, y - yo, st)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 960, in event
    rv = i.event(ev, x - xo, y - yo, cst)
  File "/usr/local/apps/ddlc/cb/renpy/display/layout.py", line 232, in event
    rv = d.event(ev, x - xo, y - yo, st)
  File "/usr/local/apps/ddlc/cb/renpy/display/behavior.py", line 889, in event
    return handle_click(self.clicked)
  File "/usr/local/apps/ddlc/cb/renpy/display/behavior.py", line 824, in handle_click
    rv = run(action)
  File "/usr/local/apps/ddlc/cb/renpy/display/behavior.py", line 306, in run
    return action(*args, **kwargs)
  File "renpy/common/00action_file.rpy", line 357, in __call__
    renpy.save(fn, extra_info=save_name)
  File "/usr/local/apps/ddlc/cb/renpy/loadsave.py", line 286, in save
    dump((roots, renpy.game.log), logf)
  File "/usr/local/apps/ddlc/cb/renpy/loadsave.py", line 45, in dump
    cPickle.dump(o, f, cPickle.HIGHEST_PROTOCOL)
PicklingError: Can't pickle <class 'store.Poem'>: it's not the same object as store.Poem

While running game code:
  File "renpy/common/00gamemenu.rpy", line 173, in script
    $ ui.interact()
  File "renpy/common/00gamemenu.rpy", line 173, in <module>
    $ ui.interact()
  File "renpy/common/00action_file.rpy", line 357, in __call__
    renpy.save(fn, extra_info=save_name)
PicklingError: Can't pickle <class 'store.Poem'>: it's not the same object as store.Poem