image inpainting error

I did your usage guide for image inpainting.

PartialConv2d(self.inplanes, planes * block.expansion, kernel_size=1, stride=stride, bias=False, **multi_channel=True, return_mask=True**)

and started to run main.py
but after partialconv, the code error is occured with this message 

AttributeError: 'tuple' object has no attribute 'dim'

How can I solve this error?
