take sample original name as single value not array

pipes/WDL/workflows/scaffold_and_refine_multitaxa.wdl

@@ -1,7 +1,6 @@
 version 1.0
 
 import "../tasks/tasks_assembly.wdl" as assembly
-import "../tasks/tasks_metagenomics.wdl" as metagenomics
 import "../tasks/tasks_ncbi.wdl" as ncbi
 import "../tasks/tasks_reports.wdl" as reports
 import "../tasks/tasks_utils.wdl" as utils
@@ -17,15 +16,15 @@ workflow scaffold_and_refine_multitaxa {
 
     input {
         String  sample_id
-        Array[String] sample_names
+        String? sample_name
         File    reads_unmapped_bam
         File    contigs_fasta
 
         File    taxid_to_ref_accessions_tsv
     }
 
     Int    min_scaffold_unambig = 10 # in base-pairs; any scaffolded assembly < this length will not be refined/polished
-    String sample_original_name = flatten([sample_names, [sample_id]])[0]
+    String sample_original_name = select_first([sample_name, sample_id])
 
     # download (multi-segment) genomes for each reference, fasta filename = colon-concatenated accession list
     scatter(taxon in read_tsv(taxid_to_ref_accessions_tsv)) {