Hclust2.py TypeError: 'NoneType' object is not iterable

Hello. I am trying to create the heatmap with hclust2.py which is working fine. But when I am trying to add “–no_sclustering” or “–no_fclustering” parameter it is showing following error.

Traceback (most recent call last):
File “/Users/research/miniconda3/envs/mpa/bin/hclust2.py”, line 825, in
File “/Users/research/miniconda3/envs/mpa/bin/hclust2.py”, line 801, in hclust2_main
cl = HClustering( distm.get_s_dm(), distm.get_f_dm(), args = args )
File “/Users/research/miniconda3/envs/mpa/bin/hclust2.py”, line 371, in init
self.s_dm=[0.0 if np.isnan(x) else x for x in s_dm]
TypeError: ‘NoneType’ object is not iterable

And I am using following command

hclust2.py -i CAD_species.txt -o CAD_species.png --ftop 42 --f_dist_f correlation --s_dist_f braycurtis --cell_aspect_ratio 1 --fperc 99 --flabel_size 4 --log_scale --legend_file CAD.legend.png --max_flabel_len 100 --metadata_height 0.05 --flabel_size 7 --slabel_size 7 --dpi 500 --slinkage complete --metadata_rows 1 -s --no_sclustering

I am not sure what is the problem. I have successfully created a heatmap without no_clustering parameter. Any help would be appreciated.