title: get product variation parent product
body: <p>How I can get variation parent product ID.</p>
  <p>EXAMPLE:
  I have product with ID 35
  and this product has two variations colors - red (ID 351), black (ID 352)</p>
  <p>My code:
  <code> $product = wc_get_product(get_the_ID()); //get_the_ID() is ID 351 and I need this parent ID 35</code></p>