code: def text_definition(self, nid):
          
          tdefs = []
          meta = self._meta(nid)
          if 'definition' in meta:
              obj = meta['definition']
              return TextDefinition(nid, **obj)
          else:
              return None
docs: Retrieves logical definitions for a class or relation id
  
          Arguments
          ---------
          nid : str
              Node identifier for entity to be queried
  
          Returns
          -------
          TextDefinition