diff --git a/bindings/python/src/processors.rs b/bindings/python/src/processors.rs
index e77b78fb..3d17f679 100644
--- a/bindings/python/src/processors.rs
+++ b/bindings/python/src/processors.rs
@@ -8,31 +8,31 @@ pub struct PostProcessor {
     pub processor: Container<dyn tk::tokenizer::PostProcessor + Sync>,
 }
 
-#[pyclass]
+#[pyclass(extends=PostProcessor)]
 pub struct BertProcessing {}
 #[pymethods]
 impl BertProcessing {
-    #[staticmethod]
-    fn new(sep: (String, u32), cls: (String, u32)) -> PyResult<PostProcessor> {
-        Ok(PostProcessor {
+    #[new]
+    fn new(obj: &PyRawObject, sep: (String, u32), cls: (String, u32)) -> PyResult<()> {
+        Ok(obj.init(PostProcessor {
             processor: Container::Owned(Box::new(tk::processors::bert::BertProcessing::new(
                 sep, cls,
             ))),
-        })
+        }))
     }
 }
 
 
-#[pyclass]
+#[pyclass(extends=PostProcessor)]
 pub struct RobertaProcessing {}
 #[pymethods]
 impl RobertaProcessing {
-    #[staticmethod]
-    fn new(sep: (String, u32), cls: (String, u32)) -> PyResult<PostProcessor> {
-        Ok(PostProcessor {
+    #[new]
+    fn new(obj: &PyRawObject, sep: (String, u32), cls: (String, u32)) -> PyResult<()> {
+        Ok(obj.init(PostProcessor {
             processor: Container::Owned(Box::new(tk::processors::roberta::RobertaProcessing::new(
                 sep, cls,
             ))),
-        })
+        }))
     }
-}
\ No newline at end of file
+}
diff --git a/bindings/python/tokenizers/implementations/bert_wordpiece.py b/bindings/python/tokenizers/implementations/bert_wordpiece.py
index dfc7c66d..6920bd27 100644
--- a/bindings/python/tokenizers/implementations/bert_wordpiece.py
+++ b/bindings/python/tokenizers/implementations/bert_wordpiece.py
@@ -7,20 +7,23 @@ from .base_tokenizer import BaseTokenizer
 
 from typing import Optional, List, Union
 
+
 class BertWordPieceTokenizer(BaseTokenizer):
     """ Bert WordPiece Tokenizer """
 
-    def __init__(self,
-                 vocab_file: Optional[str]=None,
-                 add_special_tokens: bool=True,
-                 unk_token: str="[UNK]",
-                 sep_token: str="[SEP]",
-                 cls_token: str="[CLS]",
-                 clean_text: bool=True,
-                 handle_chinese_chars: bool=True,
-                 strip_accents: bool=True,
-                 lowercase: bool=True,
-                 wordpieces_prefix: str="##"):
+    def __init__(
+        self,
+        vocab_file: Optional[str] = None,
+        add_special_tokens: bool = True,
+        unk_token: str = "[UNK]",
+        sep_token: str = "[SEP]",
+        cls_token: str = "[CLS]",
+        clean_text: bool = True,
+        handle_chinese_chars: bool = True,
+        strip_accents: bool = True,
+        lowercase: bool = True,
+        wordpieces_prefix: str = "##",
+    ):
 
         if vocab_file is not None:
             tokenizer = Tokenizer(WordPiece.from_files(vocab_file, unk_token=unk_token))
@@ -44,9 +47,8 @@ class BertWordPieceTokenizer(BaseTokenizer):
             if cls_token_id is None:
                 raise TypeError("cls_token not found in the vocabulary")
 
-            tokenizer.post_processor = BertProcessing.new(
-                (sep_token, sep_token_id),
-                (cls_token, cls_token_id)
+            tokenizer.post_processor = BertProcessing(
+                (sep_token, sep_token_id), (cls_token, cls_token_id)
             )
         tokenizer.decoders = decoders.WordPiece(prefix=wordpieces_prefix)
 
diff --git a/bindings/python/tokenizers/processors/__init__.pyi b/bindings/python/tokenizers/processors/__init__.pyi
index 8508a122..4c037eae 100644
--- a/bindings/python/tokenizers/processors/__init__.pyi
+++ b/bindings/python/tokenizers/processors/__init__.pyi
@@ -16,8 +16,7 @@ class BertProcessing:
         - a CLS token
     """
 
-    @staticmethod
-    def new(sep: Tuple[str, int], cls: Tuple[str, int]) -> PostProcessor:
+    def __init__(self, sep: Tuple[str, int], cls: Tuple[str, int]) -> None:
         """ Instantiate a new BertProcessing with the given tokens
 
         Args:
@@ -32,7 +31,6 @@ class BertProcessing:
         """
         pass
 
-
 class RobertaProcessing:
     """ RobertaProcessing
 
@@ -42,8 +40,7 @@ class RobertaProcessing:
         - a CLS token
     """
 
-    @staticmethod
-    def new(sep: Tuple[str, int], cls: Tuple[str, int]) -> PostProcessor:
+    def __init__(self, sep: Tuple[str, int], cls: Tuple[str, int]) -> None:
         """ Instantiate a new RobertaProcessing with the given tokens
 
         Args:
@@ -56,4 +53,4 @@ class RobertaProcessing:
         Returns:
             PostProcessor
         """
-        pass
\ No newline at end of file
+        pass