update README

README.md

@@ -288,11 +288,11 @@ Sometimes we need to deal with some general patterns on third-party files. Like
 
 #### Allow Empty
 
-The `allow_empty?` property was designed to deal with randomic unexpected data exported from third-party. Like `DateTime` field that has `%Y%m%d` format, but in third-party file, some lines cames with `        `, or `00000000`.
+The `allow_empty` property was designed to deal with randomic unexpected data exported from third-party. Like `DateTime` field that has `%Y%m%d` format, but in third-party file, some lines cames with `        `, or `00000000`.
 
-The common return when `allow_empty?` was marked on field, is `nil`.
+The common return when `allow_empty` was marked on field, is `nil`.
 
-_Tip: `allow_empty?` could be ommitted when you not need a data saving_
+_Tip: `allow_empty` could be ommitted when you not need a data saving_
 
 ##### Example
 
@@ -302,7 +302,7 @@ _Tip: `allow_empty?` could be ommitted when you not need a data saving_
       range: 2..10
       type: DateTime
       formats:
-        allow_empty?: true
+        allow_empty: true
         format: '%d/%m/%Y'
 ```