bugfix: constant identifiers are considered as strings in hash keys but are actually subroutines
bugfix: constant identifiers are considered as strings in hash keys but are actually subroutines

Use trick from
https://stackoverflow.com/questions/96848/is-there-any-way-to-use-a-constant-as-hash-key-in-perl

Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara,Ensembl/ensembl-compara