In sub cleanup_sources_file:   checks that $id is not an empty string   else   warns that $id is an empty string
In sub cleanup_sources_file:
  checks that $id is not an empty string
  else
  warns that $id is an empty string

Ensembl/ensembl,muffato/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,muffato/ensembl,willmclaren/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,muffato/ensembl,mjg17/ensembl,at7/ensembl,james-monkeyshines/ensembl,danstaines/ensembl,mjg17/ensembl,at7/ensembl,at7/ensembl,Ensembl/ensembl,mjg17/ensembl,Ensembl/ensembl,at7/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,muffato/ensembl,willmclaren/ensembl