How to use other models for other projects??

The notebook demo contains the following part:
------------------------------------------------------------------------------------
net_encoder = ModelBuilder.build_encoder(
arch='resnet50dilated',
fc_dim=2048,
weights='ckpt/ade20k-resnet50dilated-ppm_deepsup/encoder_epoch_20.pth')
net_decoder = ModelBuilder.build_decoder(
arch='ppm_deepsup',
fc_dim=2048,
num_class=150,
weights='ckpt/ade20k-resnet50dilated-ppm_deepsup/decoder_epoch_20.pth',
use_softmax=True)
------------------------------------------------------------------------------------

I'm wondering how I can use other networks such as HRNet.
The tricky part is how to specify fc_dim, etc.
Plus, the code in "from mit_semseg.models import ModelBuilder, SegmentationModule" does not contain the code for defining the decoder part of HRNet.

Thank you in advance.