training starts off fine but when I get to the joint_epoch i get the following issue:

Traceback (most recent call last):
File "/workspace/StyleTTS2/train_finetune.py", line 707, in
main()
File "/usr/local/lib/python3.10/dist-packages/click/core.py", line 1157, in call
return self.main(*args, **kwargs)
File "/usr/local/lib/python3.10/dist-packages/click/core.py", line 1078, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python3.10/dist-packages/click/core.py", line 1434, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/lib/python3.10/dist-packages/click/core.py", line 783, in invoke
return __callback(*args, **kwargs)
File "/workspace/StyleTTS2/train_finetune.py", line 493, in main
ref_lengths, use_ind, s_trg.detach(), ref if multispeaker else None)
UnboundLocalError: local variable 'ref' referenced before assignment

can anyone help me? am i missing something? thanks