refactor _get_meps to allow meps_by_name to call it
refactor _get_meps to allow meps_by_name to call it

stfp/memopol2,yohanboniface/memopol-core,yohanboniface/memopol-core,stfp/memopol2,stfp/memopol2,yohanboniface/memopol-core