hello everyone I have a question about qtlseq https://github.com/YuSugihara/QTL-seq

I downloaded the test file and ran it in the way of example 2.

qtlseq -r reference.fasta
     -p parent.1.fastq,parent.2.fastq
     -b1 bulk_1.1.fastq,bulk_1.2.fastq
     -b2 bulk_2.1.fastq,bulk_2.2.fastq
     -n1 20
     -n2 20
     -o example_dir
     -T

However, an error occurred. The error contents are as follows.

OSError: [Errno 38] Function not implemented: 'qtlseq_ref.fasta' -> 'example/10_ref/qtlseq_ref.fasta'

Please tell me the solution or the cause of the problem