1 files changed, 5 insertions, 5 deletions

diff --git a/src/gleam/pair.gleam b/src/gleam/pair.gleam
index 1637034..4cbce53 100644
--- a/src/gleam/pair.gleam
+++ b/src/gleam/pair.gleam
@@ -1,24 +1,24 @@
-pub fn first(pair) {
+pub fn first(pair: tuple(a, b)) -> a {
   let tuple(a, _) = pair
   a
 }
 
-pub fn second(pair) {
+pub fn second(pair: tuple(a, b)) -> b {
   let tuple(_, a) = pair
   a
 }
 
-pub fn swap(pair) {
+pub fn swap(pair: tuple(a, b)) -> tuple(b, a) {
   let tuple(a, b) = pair
   tuple(b, a)
 }
 
-pub fn map_first(of pair, with fun) {
+pub fn map_first(of pair: tuple(a, b), with fun: fn(a) -> c) -> tuple(c, b) {
   let tuple(a, b) = pair
   tuple(fun(a), b)
 }
 
-pub fn map_second(of pair, with fun) {
+pub fn map_second(of pair: tuple(a, b), with fun: fn(b) -> c) -> tuple(a, c) {
   let tuple(a, b) = pair
   tuple(a, fun(b))
 }