docs: def getAttribute(self, attribute):
          """return requested attribute value or None
          """
          if type(attribute) in (list, tuple):
              if len(attribute) != 2:
                  raise LookupError, 'To access attributes must use name or (namespace,name)'
  
              ns_dict = self.attributes.get(attribute[0])
              if ns_dict is None:
                  return None
  
              return ns_dict.get(attribute[1])
  
          return self.attributes.get(attribute)