equalsTester = new EqualsTester();
    equalObject1 = new ValidTestObject(1, 2);
    equalObject2 = new ValidTestObject(1, 2);
    notEqualObject1 = new ValidTestObject(0, 2);
  }

  /** Test null reference yields error */
  public void testAddNullReference() {
    assertThrows(NullPointerException.class, () -> equalsTester.addEqualityGroup((Object) null));
  }

 * <i>endpoint</i> value, and the range is considered to be either <i>open</i> (does not include the
 * endpoint) or <i>closed</i> (includes the endpoint) on that side. With three possibilities on each
 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means

  fmt.Printf("%v\n ", mv.Value)
}
```

output:
```
map[desc:RGB colors:[red green blue]]
map[desc:CMYK colors:[cyan magenta yellow black]]
```

likewise, increasing depth level to `3` yields:
```
red
green
blue
cyan
magenta
yellow
black
```

optionally, kev:value pairs can be emitted as an individual struct:
```go

 * <i>endpoint</i> value, and the range is considered to be either <i>open</i> (does not include the
 * endpoint) or <i>closed</i> (includes the endpoint) on that side. With three possibilities on each
 * side, this yields nine basic types of ranges, enumerated below. (Notation: a square bracket
 * ({@code [ ]}) indicates that the range is closed on that side; a parenthesis ({@code ( )}) means

    equalsTester = new EqualsTester();
    equalObject1 = new ValidTestObject(1, 2);
    equalObject2 = new ValidTestObject(1, 2);
    notEqualObject1 = new ValidTestObject(0, 2);
  }

  /** Test null reference yields error */
  public void testAddNullReference() {
    assertThrows(NullPointerException.class, () -> equalsTester.addEqualityGroup((Object) null));
  }

  @Override
  public void setUp() throws Exception {
    super.setUp();
    this.equivalenceMock = new MockEquivalence();
    this.tester = EquivalenceTester.of(equivalenceMock);
  }

  /** Test null reference yields error */
  public void testOf_nullPointerException() {
    assertThrows(NullPointerException.class, () -> EquivalenceTester.of(null));
  }

  public void testTest_noData() {
    tester.test();
  }

  @Override
  public void setUp() throws Exception {
    super.setUp();
    this.equivalenceMock = new MockEquivalence();
    this.tester = EquivalenceTester.of(equivalenceMock);
  }

  /** Test null reference yields error */
  public void testOf_nullPointerException() {
    assertThrows(NullPointerException.class, () -> EquivalenceTester.of(null));
  }

  public void testTest_noData() {
    tester.test();
  }

and <code>T</code> itself may not be
a pointer type. The unqualified type name acts as the field name.
</p>

<pre>
// A struct with four embedded fields of types T1, *T2, P.T3 and *P.T4
struct {
	T1        // field name is T1
	*T2       // field name is T2
	P.T3      // field name is T3
	*P.T4     // field name is T4
	x, y int  // field names are x and y
}
</pre>

<p>

 * that order.
 *
 * <p>By default, {@code Splitter}'s behavior is simplistic and unassuming. The following
 * expression:
 *
 * <pre>{@code
 * Splitter.on(',').split(" foo,,,  bar ,")
 * }</pre>
 *
 * ... yields the substrings {@code [" foo", "", "", " bar ", ""]}. If this is not the desired
 * behavior, use configuration methods to obtain a <i>new</i> splitter instance with modified
 * behavior:
 *
 * <pre>{@code

	left, right *Tree[K, V]
	key         K
	value       V
}

func (t *Tree[K, V]) walk(yield func(key K, val V) bool) bool {
	return t == nil || t.left.walk(yield) && yield(t.key, t.value) && t.right.walk(yield)
}

func (t *Tree[K, V]) Walk(yield func(key K, val V) bool) {
	t.walk(yield)
}

// walk tree t in-order
var t Tree[string, int]
for k, v := range t.Walk {
	// process k, v