code: def find_all(self, kw: YangIdentifier,
                   pref: YangIdentifier = None) -> List["Statement"]:
          
          return [c for c in self.substatements
                  if c.keyword == kw and c.prefix == pref]
docs: Return the list all substatements with the given keyword and prefix.
  
          Args:
              kw: Statement keyword (local part for extensions).
              pref: Keyword prefix (``None`` for built-in statements).