UnboundLocalError: local variable 'annovar_outfile' referenced before assignment

[nameOnStone]

when set args "--input_type=VCF_m" it will be an error ;
the command is
python InterVar-master/Intervar.py -b hg38 -i ./trio.vcf --input_type=VCF_m -d db/GRCh38/Annovar/ --skip_annovar -t db/InterVar/intervardb/ -o ./trio.mvcf > log 2> err

log said:

Traceback (most recent call last):
File "InterVar-master/Intervar.py", line 2124, in
main()
File "InterVar-master/Intervar.py", line 2107, in main
print ("Notice: The InterVar for VCF with multiple samples is finished, the output file is as [ %s..intervar ]" % annovar_outfile)
UnboundLocalError: local variable 'annovar_outfile' referenced before assignment

is it a BUG? thank you