pass variable is required, even if empty
pass variable is required, even if empty

willmclaren/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,ens-lgil/ensembl-rest,willmclaren/ensembl-rest,willmclaren/ensembl-rest,ens-lgil/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest,helensch/ensembl-rest