csvstack and one filename

Created by: yn

I like to use csvstack from a shell script like this:

for d in results/*; do
    t=$(basename $d)
    psql -c "drop table $t;"
    csvstack results/$t/* | csvsql --insert --db "postgresql://localhost" --no-inference --no-constraints --tables $t 
done

if there's only one CSV file in a subdirectory of results/ then csvstack errors out. Can CSVstack do something "default" like just echo the input file instead of erroring out? I am happy to submit a PR if you guys think this feature would be accepted.