Write a function top10() that returns the 10 most common values in a (sorted) vector, along with their counts. Apply your function to the column Father in the hafu dataset and store your results in an object called Father_top10 and do the same for the column Mother and store these results in Mother_top10.

Hint: Be aware of missing values which should also be returned in the counts!

(from: Cotton, 2013, Learning R, O’Reilly)