 liability-scale heritabilities in <code>h2_vec</code>,
<code>genetic_corrmat</code>, <code>full_corrmat</code>, <code>out</code> and <code>tol</code> are of the
required form, then the function returns a tibble with at least six columns (depending
on the length of out).
The first two columns correspond to the columns <code>fam_id</code> and <code>pid</code> present in
the tibble <code>family</code>.
If <code>out</code> is equal to <code>c(1)</code> or <code>c("genetic")</code>, the third and fourth columns