docs: def merge_domaindata(self, docnames, otherdata):
          """Merge in data regarding *docnames* from a different domaindata inventory
          (coming froma subprocess in a parallel build).
          """
          for fullname, (fn, objtype) in otherdata['objects'].items():
              if fn in docnames:
                  self.data['objects'][fullname] = (fn, objtype)
          for modname, data in otherdata['modules'].items():
              if data[0] in docnames:
                  self.data['modules'][modname] = data
          for labelname, data in otherdata['labels'].items():
              if data[0] in docnames:
                  self.data['labels'][labelname] = data
          for anonlabelname, data in otherdata['anonlabels'].items():
              if data[0] in docnames:
                  self.data['anonlabels'][anonlabelname] = data