===
Let block
===
x = let y = 5
        z = 1
        y + z
---
(unison
    (term_declaration
        (term_definition
            (regular_identifier)
            (kw_equals)
            (exp_let
                (kw_let)
                (term_declaration
                    (term_definition
                        (regular_identifier)
                        (kw_equals)
                        (nat)))
                (term_declaration
                    (term_definition
                        (regular_identifier)
                        (kw_equals)
                        (nat)))
                (regular_identifier)
                (operator)
                (regular_identifier)))))
