code: private SemanticSpace getSSpace(String name) {
          String aliased = aliasToFileName.get(name);
          return (aliased != null) 
              ? fileNameToSSpace.get(aliased)
              : fileNameToSSpace.get(name);
      }
docs: Returns the {@code SemanticSpace} linked to the name, either as an alias
  or as a file name.
  
  @param name the alias or file name of a loaded semantic space
  
  @return the loaded semantic space or {@code null} no space with the
  provided name exists