diff --git a/Cargo.lock b/Cargo.lock
index 3eb89c1..13582f7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -252,9 +252,9 @@ checksum = "7fcaabb2fef8c910e7f4c7ce9f67a1283a1715879a7c230ca9d6d1ae31f16d91"
 
 [[package]]
 name = "els"
-version = "0.1.25-nightly.2"
+version = "0.1.25-nightly.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2718d575740fbdcd8f91262e3f3c100190ee74344c22a58b8bb201b91a5b4aa"
+checksum = "93c1aa5d03b6f0b4081797248b7149a30ea7016f22d865210947ebe851189a25"
 dependencies = [
  "erg_common",
  "erg_compiler",
@@ -274,9 +274,9 @@ dependencies = [
 
 [[package]]
 name = "erg_common"
-version = "0.6.13-nightly.2"
+version = "0.6.13-nightly.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9ffa2366ff45440b95e7854897574238b17e2ceeae419563f6eacb764dd294e"
+checksum = "a00c25d402e2a7b0a25c6104cce9556d05e063193f4c1f793a26265497a6586e"
 dependencies = [
  "backtrace-on-stack-overflow",
  "hermit-abi",
@@ -286,9 +286,9 @@ dependencies = [
 
 [[package]]
 name = "erg_compiler"
-version = "0.6.13-nightly.2"
+version = "0.6.13-nightly.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "920553db0288f2d09ca30f218aeb810874071e898963591b0b3b2fc13ea7b8a6"
+checksum = "430581161391be0ab5d2045fc66830ba38d29fc435539050f69abfa9dc062e34"
 dependencies = [
  "erg_common",
  "erg_parser",
@@ -296,9 +296,9 @@ dependencies = [
 
 [[package]]
 name = "erg_parser"
-version = "0.6.13-nightly.2"
+version = "0.6.13-nightly.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6c591017fbe24f97c1bcc7b8a0ba52c68129c9a039ac169c12e804703f94a4b"
+checksum = "576308cf389047744b0bbacd6715092e07f049dd06be92299b06d04a8b9499cf"
 dependencies = [
  "erg_common",
  "unicode-xid 0.2.4",
diff --git a/Cargo.toml b/Cargo.toml
index 24afcff..4c56929 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,9 +22,9 @@ edition = "2021"
 repository = "https://github.com/mtshiba/pylyzer"
 
 [workspace.dependencies]
-erg_common = { version = "0.6.13-nightly.2", features = ["py_compat", "els"] }
-erg_compiler = { version = "0.6.13-nightly.2", features = ["py_compat", "els"] }
-els = { version = "0.1.25-nightly.2", features = ["py_compat"] }
+erg_common = { version = "0.6.13-nightly.3", features = ["py_compat", "els"] }
+erg_compiler = { version = "0.6.13-nightly.3", features = ["py_compat", "els"] }
+els = { version = "0.1.25-nightly.3", features = ["py_compat"] }
 rustpython-parser = "0.1.2"
 # erg_compiler = { git = "https://github.com/erg-lang/erg", branch = "main", features = ["py_compat", "els"] }
 # erg_common = { git = "https://github.com/erg-lang/erg", branch = "main", features = ["py_compat", "els"] }
diff --git a/crates/py2erg/convert.rs b/crates/py2erg/convert.rs
index b6c58f8..3e58b81 100644
--- a/crates/py2erg/convert.rs
+++ b/crates/py2erg/convert.rs
@@ -525,7 +525,12 @@ impl ASTConverter {
                 };
                 let lhs = self.convert_type_spec(elements.remove(0));
                 let rhs = self.convert_type_spec(elements.remove(0));
-                TypeSpec::or(lhs, rhs)
+                let mut union = TypeSpec::or(lhs, rhs);
+                for elem in elements {
+                    let t = self.convert_type_spec(elem);
+                    union = TypeSpec::or(union, t);
+                }
+                union
             }
             "Optional" => {
                 let loc = args.location;
diff --git a/tests/collections.py b/tests/collections.py
index da3d694..8842299 100644
--- a/tests/collections.py
+++ b/tests/collections.py
@@ -20,3 +20,7 @@ _ = dic2["c"] # OK
 t: tuple[int, str] = (1, "a")
 _ = t[0] == 1 # OK
 _ = t[1] == 1 # ERR
+
+def f(s: Str): return None
+for i in getattr(1, "aaa", ()):
+    f(i)
diff --git a/tests/typespec.py b/tests/typespec.py
index a8404fe..eb68867 100644
--- a/tests/typespec.py
+++ b/tests/typespec.py
@@ -29,3 +29,10 @@ _: Iterable[int] = ["a"] # ERR
 
 _: Mapping[str, int] = {"a": 1, "c": 2} # OK
 _: Mapping[str, int] = {1: "a", 2: "b"} # ERR
+
+def f(x: Union[int, str, None]):
+    pass
+# OK
+f(1)
+f("a")
+f(None)