docs: def get_lookup(self, lookup_name):
          """Fetch Lookup by name"""
          from protean.core.repository import BaseLookup
          lookup = self._get_lookup(lookup_name)
  
          # If unable to find Lookup, or if Lookup is the wrong class, raise Error
          if lookup is None or (lookup is not None and not issubclass(lookup, BaseLookup)):
              raise NotImplementedError
  
          return lookup