                    times. This generator succeeds as long as its embedded generator
                      <code class="computeroutput"><span class="identifier">a</span></code> does not
                      fail and as long as the associated attribute (container) contains
                      at least <code class="computeroutput"><span class="identifier">num1</span></code>
                      elements (unless the underlying output stream reports an error).
                      If the associated attribu