Check if a particular key/value pair exists before trying to store it; warn and don't store if it's already there.
Check if a particular key/value pair exists before trying to store it; warn and don't store if it's already there.

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