feat: add list flattern functions for the collectionutil module

Signed-off-by: peefy <[email protected]>

collectionutil/kcl.mod

@@ -1,4 +1,5 @@
 [package]
 name = "collectionutil"
-version = "0.0.1"
+version = "0.0.2"
 description = "`collectionutil` is a kcl module for list and config values"
+

collectionutil/main.k

@@ -2,3 +2,7 @@
 to_str_set = lambda items: [str] {
     [item for item in {item = None for item in items}]
 }
+
+list_flattern = lambda items: [any] -> [any] {
+    sum(items, [])
+}

collectionutil/main_test.k

@@ -0,0 +1,7 @@
+test_to_str_set = lambda {
+    assert to_str_set(["a", "a", "b"]) == ["a", "b"]
+}
+
+test_list_flattern = lambda {
+    assert list_flattern([[1, 2], [3, 4]]) == [1, 2, 3, 4]
+}