Using the type notation, write two oz functions for determining the sum of the elements of:

a) nested list, given by:

& λτ; nlist t& γτ; : : =

nil |

& λτ; nlist t> '|' & λτ; nlist t> |

t '|' & λτ; nlist t& γτ; (t is not nil nor a cons)

b) binary tree, given by:

leaf |

tree(value: t

left:
right: )

for example, the call {sumnestedlist [[1 2] [3 5] [3 [1]]]} will display 15, and the call

{sumbinarytree tree(value: 2

left: tree(value: 3

left: tree(value: 5

left: leaf

right: leaf)

right: leaf)

right: tree(value: 4

left: leaf

right: leaf)

)}

will display 14.