No. Site is site, PhEDEx node is PhEDEx node, they don't need to be identical. For instance, site is T1_DE_DESY and that doesn't exists as a PhEDEx node, it's T1_DE_DESY_Disk and T1_DE_DESY_MSS. This is correct, you get a list of PhEDEx nodes for every site.

What's wrong here is how this is used. We don't want make a mapping from site to PhEDEx node at all here, we want to use PhEDEx nodes for subscription in the first place. Like farther up in the same method there is a

site = subInfo['site']

which should really be

phedexNode = subInfo['phedexNode']

Ie. the PhEDEx node for a subscription needs to be provided by the requestor.