diff --git a/a.k b/a.k
new file mode 100644
index 00000000..e69de29b
diff --git a/docs/reference/lang/spec/kcl-spec.md b/docs/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/docs/reference/lang/spec/kcl-spec.md
+++ b/docs/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/current/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/current/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/current/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/current/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.10/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.10/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.10/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.10/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.4/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.4/reference/lang/spec/kcl-spec.md
index 3d36c364..4b541e61 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.4/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.4/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.5/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.5/reference/lang/spec/kcl-spec.md
index 63a9d6e7..c61b92ae 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.5/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.5/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.6/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.6/reference/lang/spec/kcl-spec.md
index 63a9d6e7..c61b92ae 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.6/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.6/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.7/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.7/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.7/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.7/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.8/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.8/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.8/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.8/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.9/reference/lang/spec/kcl-spec.md b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.9/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.9/reference/lang/spec/kcl-spec.md
+++ b/i18n/zh-CN/docusaurus-plugin-content-docs/version-0.9/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.10/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.10/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/versioned_docs/version-0.10/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.10/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.4/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.4/reference/lang/spec/kcl-spec.md
index 3d36c364..4b541e61 100644
--- a/versioned_docs/version-0.4/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.4/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.5/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.5/reference/lang/spec/kcl-spec.md
index 63a9d6e7..c61b92ae 100644
--- a/versioned_docs/version-0.5/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.5/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.6/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.6/reference/lang/spec/kcl-spec.md
index 63a9d6e7..c61b92ae 100644
--- a/versioned_docs/version-0.6/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.6/reference/lang/spec/kcl-spec.md
@@ -141,7 +141,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.7/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.7/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/versioned_docs/version-0.7/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.7/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.8/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.8/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/versioned_docs/version-0.8/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.8/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type
diff --git a/versioned_docs/version-0.9/reference/lang/spec/kcl-spec.md b/versioned_docs/version-0.9/reference/lang/spec/kcl-spec.md
index e2f217dc..26e22eea 100644
--- a/versioned_docs/version-0.9/reference/lang/spec/kcl-spec.md
+++ b/versioned_docs/version-0.9/reference/lang/spec/kcl-spec.md
@@ -137,7 +137,7 @@ basic_type: STRING_TYPE | INT_TYPE | FLOAT_TYPE | BOOL_TYPE | ANY_TYPE
 compound_type: list_type | dict_type
 list_type: LEFT_BRACKETS (type)? RIGHT_BRACKETS
 dict_type: LEFT_BRACE (type)? COLON (type)? RIGHT_BRACE
-literal_type: string | number | TRUE | FALSE | NONE
+literal_type: string | number | TRUE | FALSE
 
 //////////// type alias ////////////
 type_alias_stmt: TYPE NAME ASSIGN type