File systemFile = artifact.getFile();

            if (systemFile == null) {
                throw new ArtifactNotFoundException("System artifact: " + artifact + " has no file attached", artifact);
            }

            if (!systemFile.exists()) {
                throw new ArtifactNotFoundException(
                        "System artifact: " + artifact + " not found in path: " + systemFile, artifact);

  }

  /**
   * Guaranteed to throw an exception and leave the multimap unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */
  @CanIgnoreReturnValue
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public final ImmutableSet<V> removeAll(@CheckForNull Object key) {
    throw new UnsupportedOperationException();
  }

        @ParametricNullness V value) {
      throw new UnsupportedOperationException();
    }

    @Override
    public void putAll(Table<? extends R, ? extends C, ? extends V> table) {
      throw new UnsupportedOperationException();
    }

    @Override
    @CheckForNull
    public V remove(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
      throw new UnsupportedOperationException();
    }

    resetMap(createArrayWithNullValue());
  }

  /**
   * Equivalent to {@link #expectMissingKeys(Object[]) expectMissingKeys} {@code (null)} except that
   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullKeyMissingWhenNullKeysUnsupported(String message) {
    try {

        Map<String, PromptResultItemIF> result = prompt.prompt(
                context.header, dispatcherPrompt(prompt.getPromptBuilder()).build());
        if (result == null) {
            throw new InterruptedException();
        }
        if (NONE.equals(result.get("defaultDispatcher").getResult())) {
            context.terminal
                    .writer()
                    .println(messageBuilderFactory

        assertArgumentNotNull("factory", factory);
        assertArgumentNotNull("schema", schema);

        try {
            return factory.newSchema(schema);
        } catch (final SAXException e) {
            throw new SAXRuntimeException(e);
        }
    }

    /**
     * 指定の{@link SchemaFactory}を使用して{@link Schema}を作成します。
     *
     * @param factory
     *            {@link SchemaFactory}。{@literal null}であってはいけません

          return null;
        }

        @Override
        public Range<Comparable<?>> span() {
          throw new NoSuchElementException();
        }

        @Override
        public void put(Range<Comparable<?>> range, Object value) {
          checkNotNull(range);
          throw new IllegalArgumentException(
              "Cannot insert range " + range + " into an empty subRangeMap");
        }

                    cacheAddress( name, addr );
                    updateLookupTable( name );
                }
            }
        }
        if( addr == UNKNOWN_ADDRESS ) {
            throw new UnknownHostException( name.toString() );
        }
        return addr;
    }

    private static Object checkLookupTable( Name name ) {
        Object obj;

        synchronized( LOOKUP_TABLE ) {

  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    NavigableMap<String, Integer> map = new SafeTreeMap<>();
    map.put("one", 1);
    map.put("two", 2);
    map.put("three", 3);
    return SerializableTester.reserialize(map);
  }

  @Override
  protected SortedMap<String, Integer> makeEmptyMap() throws UnsupportedOperationException {

        url = "https://api.github.com/markdown/raw".toHttpUrl(),
        body = postBody.toRequestBody(MEDIA_TYPE_MARKDOWN),
      )

    client.newCall(request).execute().use { response ->
      if (!response.isSuccessful) throw IOException("Unexpected code $response")

      println(response.body.string())
    }
  }

  companion object {
    val MEDIA_TYPE_MARKDOWN = "text/x-markdown; charset=utf-8".toMediaType()
  }
}