code: public void assertNotEqual(Description description, Object actual, Object other) {
      if (areEqual(actual, other)) {
        throw failures.failure(description, shouldNotBeEqual(actual, other));
      }
    }
docs: Asserts that two objects are not equal.
  
  @param description the description of the <em>actual</em> object.
  @param actual the <em>actual</em> object.
  @param other the object to compare {@code actual} to.
  @throws AssertionError if {@code actual} is equal to {@code other}.