{* ../../docs_src/python_types/tutorial005.py hl[1] *}

### Generic types with type parameters { #generic-types-with-type-parameters }

There are some data structures that can contain other values, like `dict`, `list`, `set` and `tuple`. And the internal values can have their own type too.

These types that have internal types are called "**generic**" types. And it's possible to declare them, even with their internal types.

        String value = null;
        boolean haveValue = false;
        if (encoding != null) {
            try {
                value = item.getString(encoding);
                haveValue = true;
            } catch (final Exception e) {}
        }
        if (!haveValue) {
            try {
                value = item.getString(Charset.forName("ISO-8859-1"));

    };
    int[] bases = {2, 5, 7, 8, 10, 16};
    for (int base : bases) {
      for (String x : tests) {
        BigInteger xValue = new BigInteger(x, 16);
        long xLong = xValue.longValue(); // signed
        assertThat(UnsignedLongs.toString(xLong, base)).isEqualTo(xValue.toString(base));
      }
    }
  }

  public void testJoin() {
    assertThat(UnsignedLongs.join(",")).isEmpty();

        Map<String, String> dataMap = new HashMap<>();
        dataMap.put("key1", "value1");
        dataMap.put("key2", "");
        dataMap.put("key3", null);

        // Test with existing value
        String result1 = (String) method.invoke(crawler, dataMap, "key1", "default");
        assertEquals("value1", result1);

        // Test with empty value
        String result2 = (String) method.invoke(crawler, dataMap, "key2", "default");

    public static final String SELF_COMBINATION_MODE_ATTRIBUTE = "combine.self";
    /** Value indicating the element should be completely overridden */
    public static final String SELF_COMBINATION_OVERRIDE = "override";
    /** Value indicating the element should be merged */
    public static final String SELF_COMBINATION_MERGE = "merge";
    /** Value indicating the element should be removed */

  @Override
  public final boolean containsKey(@Nullable Object key) {
    return Maps.safeContainsKey(delegate, key);
  }

  @Override
  public final boolean containsValue(@Nullable Object value) {
    return delegate.containsValue(value);
  }

  @Override
  public @Nullable V get(@Nullable Object key) {
    return (key == null) ? null : Maps.safeGet(delegate, key);
  }

  @Override

   * escaper to escape attribute values. Use {@link #xmlContentEscaper} if the output can appear in
   * element content or {@link #xmlAttributeEscaper} in attribute values.
   *
   * <p>This escaper substitutes {@code 0xFFFD} for non-whitespace control characters and the
   * character values {@code 0xFFFE} and {@code 0xFFFF} which are not permitted in XML. For more

    public String createdBy;

    /**
     * The timestamp when this access token was created.
     * Stored as a long value representing milliseconds since epoch.
     */
    @ValidateTypeFailure
    public Long createdTime;

    /**
     * Initializes the form with default values for creation.
     * Sets the CRUD mode to CREATE and populates created by and created time fields

        @DisplayName("Should have correct constant values for PreauthIntegrityNegotiateContext")
        void testPreauthConstants() {
            assertEquals(0x1, PreauthIntegrityNegotiateContext.NEGO_CTX_PREAUTH_TYPE);
            assertEquals(0x1, PreauthIntegrityNegotiateContext.HASH_ALGO_SHA512);
        }

        @Test
        @DisplayName("Should have correct constant values for EncryptionNegotiateContext")

type Metadata struct {
	Items []struct {
		Key   string
		Value string
	}
}

// Set add items, duplicate items get replaced.
func (s *Metadata) Set(k, v string) {
	for i, item := range s.Items {
		if item.Key == k {
			s.Items[i] = struct {
				Key   string
				Value string
			}{
				Key:   k,
				Value: v,
			}
			return
		}
	}
	s.Items = append(s.Items, struct {