How to run with custom reference (es assembly)

[telatin]

I'd like to run bamsnap with a custom reference (assembly output). This works disabling the "gene" track with:

bamsnap -draw coordinates bamplot coverage base \ 
   -out test.png -bam aln.bam -pos NODE_1_length_31064_cov_4.851893:1000 -ref contigs.fasta

A warning could be useful to figure this out.