Bootstrap4 align-self-center not working?

Question

Bootstrap

Hello, tell me why align-self-center does not work in Bootstrap4

<div class="col align-self-center">
                  <div class="nextpost">
                    <a href="#">Больше статей</a>
                  </div>
                </div>

I want to center it in the center, but something doesn’t work, as it was in the left corner and so

Answer 1

Everything works
https://codepen.io/kickerock/pen/MdpBEb
d-flex add
<div class="col d-flex align-self-center">