Error when trying to run script

[Timzladen]

File "taxonomy_assignment_BLAST.py", line 196, in
do_blast(args.sequence_file,args.blast_database,blast_file)
File "taxonomy_assignment_BLAST.py", line 188, in do_blast
log_and_print(err)
File "taxonomy_assignment_BLAST.py", line 76, in log_and_print
log_file_name_handle.writelines(statement+'\n')
TypeError: can't concat str to bytes

No idea what to do.