code: @CheckForNull
      public static PrivateKey loadPrivateKey(final String keypem) throws IOException, NoSuchAlgorithmException,
              InvalidKeySpecException {
          try (StringReader certReader = new StringReader(keypem);
               BufferedReader reader = new BufferedReader(certReader)) {
              return loadPrivateKey(reader);
          }
      }
docs: Return KeyPair from "key.pem"