how to train my own datasets with different num_class

[Kenneth-X]

using centermask_V_99_eSE_FPN_ms_3x.yaml and centermask-V2-99-FPN-ms-3x.pth
it occurs this bug:

self.class.name, "\n\t".join(error_msgs)))
RuntimeError: Error(s) in loading state_dict for GeneralizedRCNN:
size mismatch for roi_heads.mask.predictor.mask_fcn_logits.weight: copying a param with shape torch.Size([81, 256, 1, 1]) from checkpoint, theshape in current model is torch.Size([2, 256, 1, 1]).
size mismatch for roi_heads.mask.predictor.mask_fcn_logits.bias: copying a param with shape torch.Size([81]) from checkpoint, the shape in current model is torch.Size([2]).
size mismatch for roi_heads.maskiou.predictor.maskiou.weight: copying a param with shape torch.Size([81, 1024]) from checkpoint, the shape in current model is torch.Size([2, 1024]).
size mismatch for roi_heads.maskiou.predictor.maskiou.bias: copying a param with shape torch.Size([81]) from checkpoint, the shape in current model is torch.Size([2]).