anchor.diff:     * Checks that every element of [expected] is also in [actual], and that
      * every element of [actual] is also in [expected].
      */
  +  @deprecated
     static void setEquals(Iterable expected,
                           Iterable actual,
                           [String reason = null]) {
  
positive.code: part of dart.core;
  
  /**
   * Expect is used for tests that do not want to make use of the
   * Dart unit test library - for example, the core language tests.
   * Third parties are discouraged from using this, and should use
   * the expect() function in the unit test library instead for
   * test assertions.
   */
  class Expect {
    /**
     * Checks whether the expected and actual values are equal (using `==`).
     */
    static void equals(var expected, var actual, [String reason = null]) {
      if (expected == actual) return;
      String msg = _getMessage(reason);
  
negative.code:    * given tolerance. If no tolerance is given, tolerance is assumed to be the
     * value 4 significant digits smaller than the value given for expected.
     */
    @deprecated
    static void approxEquals(num expected,
                             num actual,
                             [num tolerance = null,
  