code: def rc_to_exctype(cls, rc):
          
          try:
              return _LCB_ERRNO_MAP[rc]
          except KeyError:
              newcls = _mk_lcberr(rc)
              _LCB_ERRNO_MAP[rc] = newcls
              return newcls
docs: Map an error code to an exception
  
          :param int rc: The error code received for an operation
  
          :return: a subclass of :class:`CouchbaseError`