diff --git a/crates/erg_compiler/lib/external/certifi.d/__init__.d.er b/crates/erg_compiler/lib/external/certifi.d/__init__.d.er
new file mode 100644
index 00000000..868837c5
--- /dev/null
+++ b/crates/erg_compiler/lib/external/certifi.d/__init__.d.er
@@ -0,0 +1,3 @@
+.core = pyimport "./core"
+
+{.contents!; .where!} = .core
diff --git a/crates/erg_compiler/lib/external/certifi.d/core.d.er b/crates/erg_compiler/lib/external/certifi.d/core.d.er
new file mode 100644
index 00000000..e0921f98
--- /dev/null
+++ b/crates/erg_compiler/lib/external/certifi.d/core.d.er
@@ -0,0 +1,2 @@
+.contents!: () => Str
+.where!: () => Str
diff --git a/crates/erg_compiler/lib/external/certifi.d/package.er b/crates/erg_compiler/lib/external/certifi.d/package.er
new file mode 100644
index 00000000..e69de29b
diff --git a/crates/erg_compiler/lib/external/idna.d/__init__.d.er b/crates/erg_compiler/lib/external/idna.d/__init__.d.er
new file mode 100644
index 00000000..23f1a656
--- /dev/null
+++ b/crates/erg_compiler/lib/external/idna.d/__init__.d.er
@@ -0,0 +1,18 @@
+.core = pyimport "./core"
+
+{
+    .alabel;
+    .check_bidi;
+    .check_hyphen_ok;
+    .check_initial_combiner;
+    .check_label;
+    .check_nfc;
+    .decode;
+    .encode;
+    .ulabel;
+    .uts46_remap;
+    .valid_contextj;
+    .valid_contexto;
+    .valid_label_length;
+    .valid_string_length;
+} = .core
diff --git a/crates/erg_compiler/lib/external/idna.d/core.d.er b/crates/erg_compiler/lib/external/idna.d/core.d.er
new file mode 100644
index 00000000..3d7ac0bf
--- /dev/null
+++ b/crates/erg_compiler/lib/external/idna.d/core.d.er
@@ -0,0 +1,33 @@
+.IDNAError: ClassType
+.IDNABidiError: ClassType
+.IDNABidiError <: .IDNAError
+.InvalidCodepoint: ClassType
+.InvalidCodepoint <: .IDNAError
+.InvalidCodepointContext: ClassType
+.InvalidCodepointContext <: .IDNAError
+
+.valid_label_length: (label: Str or Bytes) -> Bool
+.valid_string_length: (label: Str or Bytes, trailing_dot: Bool) -> Bool
+.check_bidi: (label: Str, check_ltr := Bool) -> Bool
+.check_initial_combiner: (label: Str) -> Bool
+.check_hyphen_ok: (label: Str) -> Bool
+.check_nfc: (label: Str) -> Bool
+.valid_contextj: (label: Str, pos: Int) -> Bool
+.valid_contexto: (label: Str, pos: Int, exception := Bool) -> Bool
+.check_label: (label: Str or Bytes) -> NoneType
+.alabel: (label: Str) -> Bytes
+.ulabel: (label: Str or Bytes) -> Str
+.uts46_remap: (domain: Str or Bytes, std3_rules := Bool, transitional := Bool) -> Str
+.encode: (
+    s: Str or Bytes,
+    strict:= Bool,
+    uts46:= Bool,
+    std3_rules:= Bool,
+    transitional:= Bool,
+) -> Bytes
+.decode: (
+    s: Str or Bytes,
+    strict:= Bool,
+    uts46:= Bool,
+    std3_rules:= Bool,
+) -> Str
diff --git a/crates/erg_compiler/lib/external/idna.d/package.er b/crates/erg_compiler/lib/external/idna.d/package.er
new file mode 100644
index 00000000..e69de29b
diff --git a/crates/erg_compiler/lib/external/packaging.d/__init__.d.er b/crates/erg_compiler/lib/external/packaging.d/__init__.d.er
new file mode 100644
index 00000000..cd8dd60d
--- /dev/null
+++ b/crates/erg_compiler/lib/external/packaging.d/__init__.d.er
@@ -0,0 +1 @@
+.version = pyimport "./version"
diff --git a/crates/erg_compiler/lib/external/packaging.d/package.er b/crates/erg_compiler/lib/external/packaging.d/package.er
new file mode 100644
index 00000000..e69de29b
diff --git a/crates/erg_compiler/lib/external/packaging.d/version.d.er b/crates/erg_compiler/lib/external/packaging.d/version.d.er
new file mode 100644
index 00000000..e7138c3e
--- /dev/null
+++ b/crates/erg_compiler/lib/external/packaging.d/version.d.er
@@ -0,0 +1,23 @@
+.Version: ClassType
+.Version <: Eq
+.Version <: Ord
+.Version.
+    epoch: Nat
+    release: (Nat, Nat, Nat)
+    pre: (Str, Nat) or NoneType
+    post: Nat or NoneType
+    dev: Nat or NoneType
+    local: Str or NoneType
+    public: Str
+    base_version: Str
+    is_prerelease: Bool
+    is_postrelease: Bool
+    is_devrelease: Bool
+    major: Nat
+    minor: Nat
+    micro: Nat
+    __call__: (ver: Str) -> .Version
+
+.InvalidVersion: ClassType
+
+.parse: (ver: Str) -> .Version
diff --git a/crates/erg_compiler/lib/external/six.d/__init__.d.er b/crates/erg_compiler/lib/external/six.d/__init__.d.er
new file mode 100644
index 00000000..9034c3b3
--- /dev/null
+++ b/crates/erg_compiler/lib/external/six.d/__init__.d.er
@@ -0,0 +1,13 @@
+.PY2: Bool
+.PY3: Bool
+
+.class_types: [Type; _]
+.intger_types: [Type; _]
+.string_types: [Type; _]
+.float_types: [Type; _]
+.text_type: Type
+.binary_type: Type
+.MAXSIZE: Nat
+
+.exec_!: (code: Str, globals := {Str: Obj}, locals := {Str: Obj}) => Obj
+.print_!: (*objs: [Obj; _], end := Str, sep := Str) => NoneType
diff --git a/crates/erg_compiler/lib/external/six.d/package.er b/crates/erg_compiler/lib/external/six.d/package.er
new file mode 100644
index 00000000..e69de29b