fixes for cases where strain and sex attributes are empty

species_data.py

@@ -129,6 +129,9 @@ class SpeciesData:
              self.sex_lowercase])["not_empty"])
 
         self.dataset_prefix = self.strain_sex
+        # If both strain and sex are empty attributes, change the dataset prefix to nothing instead of "_"
+        if self.dataset_prefix == "_":
+            self.dataset_prefix = ""
 
         self.genome_filename = "{0}_v{1}.fasta".format(self.dataset_prefix, self.genome_version)
         self.gff_filename = "{0}_OGS{1}_{2}.gff".format(self.dataset_prefix, self.ogs_version, constants.DATA_DATE.replace("-",""))