(examples-for dp

("returns nil for nil"
 (dp)
 nil)

("returns nil when everything is empty"
 (dp "" nil {} ())
 nil)

("returns the first item if not empty"
 (dp 'a "" {} ())
 a)

("returns the second item if not empty"
 (dp "" 'b "" {} ())
 b)

("returns the third item if not empty"
 (dp "" {} 'c "" {} ())
 c)

("returns the last item if not empty"
 (dp "" {} () 'd)
 d))