[ENSCORESW-783]. XS assert_ref fails with Bio::EnsEMBL::Proxy inherited object. Bug fix by calling the proxy object isa method instead of sv_derived_from.
[ENSCORESW-783].
XS assert_ref fails with Bio::EnsEMBL::Proxy inherited object.
Bug fix by calling the proxy object isa method instead of sv_derived_from.

Ensembl/ensembl-xs,Ensembl/ensembl-xs,Ensembl/ensembl-xs,Ensembl/ensembl-xs,Ensembl/ensembl-xs