fix: sync text_signature according to real default values

Author: shenxiangzhuang

bindings/python/py_src/tokenizers/trainers/__init__.pyi

@@ -99,6 +99,7 @@ class UnigramTrainer(Trainer):
         vocab_size=8000,
         show_progress=True,
         special_tokens=[],
+        initial_alphabet=[],
         shrinking_factor=0.75,
         unk_token=None,
         max_piece_length=16,
@@ -123,7 +124,7 @@ class WordLevelTrainer(Trainer):
         special_tokens (:obj:`List[Union[str, AddedToken]]`):
             A list of special tokens the model should know of.
     """
-    def __init__(self, vocab_size=30000, min_frequency=0, show_progress=True, special_tokens=None):
+    def __init__(self, vocab_size=30000, min_frequency=0, show_progress=True, special_tokens=[]):
         pass
 
 class WordPieceTrainer(Trainer):

bindings/python/src/trainers.rs

@@ -664,7 +664,7 @@ impl PyWordLevelTrainer {
     #[new]
     #[pyo3(
         signature = (**kwargs), 
-        text_signature = "(self, vocab_size=30000, min_frequency=0, show_progress=True, special_tokens=None)"
+        text_signature = "(self, vocab_size=30000, min_frequency=0, show_progress=True, special_tokens=[])"
     )]
     pub fn new(kwargs: Option<&Bound<'_, PyDict>>) -> PyResult<(Self, PyTrainer)> {
         let mut builder = tk::models::wordlevel::WordLevelTrainer::builder();
@@ -832,7 +832,7 @@ impl PyUnigramTrainer {
     #[new]
     #[pyo3(
         signature = (**kwargs),
-        text_signature = "(self, vocab_size=8000, show_progress=True, special_tokens=[], shrinking_factor=0.75, unk_token=None, max_piece_length=16, n_sub_iterations=2)"
+        text_signature = "(self, vocab_size=8000, show_progress=True, special_tokens=[], initial_alphabet=[], shrinking_factor=0.75, unk_token=None, max_piece_length=16, n_sub_iterations=2)"
     )]
     pub fn new(kwargs: Option<Bound<'_, PyDict>>) -> PyResult<(Self, PyTrainer)> {
         let mut builder = tk::models::unigram::UnigramTrainer::builder();