@When("^I push an item into the stack$")
 public void I_push_an_item_into_the_stack() {
   pushed = new Object();
   myStack.push(pushed);
 }
 @Then("^the stack contains one item$")
 public void the_stack_contains_one_item() {
   assertEquals(1, myStack.size());
 }
 @Then("^the stack contains two items$")
 public void the_stack_contains_two_items() {
   assertEquals(2, myStack.size());
 }
 @When("^I pop from the stack$")
 public void I_pop_from_the_stack() {
   Object out = myStack.pop();
   popped = out;
 }