Method push

core/src/main/java/org/apache/calcite/util/Stacks.java:48–50

Adds an element to the stack.

(List<T> stack, T element)

   * Adds an element to the stack.
   */
  public static <T> void push(List<T> stack, T element) {
    stack.add(element);
  }

  /**
   * Removes an element from the stack. Asserts of the element is not the