THis may or may not be better:

Your output:
t, r = f.cousin("o", "n")
'o' is a second cousin 0 removed from 'n'

Correct output:
t, r = f.cousin("o", "n")
'o' is a zeroth cousin 0 removed from 'n'

and

Your output:
t, r = f.cousin("f", "n")
'f' is a first cousin 1 removed from 'n'

Correct output:
t, r = f.cousin("f", "n")
'f' is a zeroth cousin 1 removed from 'n'
added more tests
full credit