code: def load_adjusted_array(self, domain, columns, dates, sids, mask):
          
          out = {}
          for col in columns:
              try:
                  loader = self._loaders.get(col)
                  if loader is None:
                      loader = self._loaders[col.unspecialize()]
              except KeyError:
                  raise ValueError("Couldn't find loader for %s" % col)
              out.update(
                  loader.load_adjusted_array(domain, [col], dates, sids, mask)
              )
          return out
docs: Load by delegating to sub-loaders.