When you dont want to litter on stackoverflow

if whatsDate not in cal.itermonthdays(2020, nowMonth.month):
         print('Правильную дату введи!')

<button class="form__signup" type="button" onclick="return false">Регистрация</button>

import asyncio

asyns def():
         ...
         await asyncio.sleep(30)
         ....

<div class="container-fluid">
  <div class="row">
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
  </div>
</div>