diff --git a/.circleci/config.yml b/.circleci/config.yml
index 1e1a13eb7ce..856211e280c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -852,7 +852,7 @@ jobs:
             - run: isort --check-only examples tests src utils
             - run: python utils/custom_init_isort.py --check_only
             - run: flake8 examples tests src utils
-            - run: python utils/style_doc.py src/transformers docs/source --max_len 119 --check_only
+            - run: doc-builder style src/transformers docs/source --max_len 119 --check_only --path_to_docs docs/source
 
     check_repository_consistency:
         working_directory: ~/transformers
diff --git a/Makefile b/Makefile
index 91d51c8f72b..424d8798c9e 100644
--- a/Makefile
+++ b/Makefile
@@ -48,13 +48,13 @@ quality:
 	isort --check-only $(check_dirs)
 	python utils/custom_init_isort.py --check_only
 	flake8 $(check_dirs)
-	python utils/style_doc.py src/transformers docs/source --max_len 119 --check_only
+	doc-builder style src/transformers docs/source --max_len 119 --check_only --path_to_docs docs/source
 
 # Format source code automatically and check is there are any problems left that need manual fixing
 
 extra_style_checks:
 	python utils/custom_init_isort.py
-	python utils/style_doc.py src/transformers docs/source --max_len 119
+	doc-builder style src/transformers docs/source --max_len 119 --path_to_docs docs/source
 
 # this target runs checks on all files and potentially modifies some of them
 
diff --git a/docs/source/_config.py b/docs/source/_config.py
index e1f270ba9c3..cd76263e9a5 100644
--- a/docs/source/_config.py
+++ b/docs/source/_config.py
@@ -7,3 +7,8 @@ INSTALL_CONTENT = """
 """
 
 notebook_first_cells = [{"type": "code", "content": INSTALL_CONTENT}]
+black_avoid_patterns = {
+    "{processor_class}": "FakeProcessorClass",
+    "{model_class}": "FakeModelClass",
+    "{object_class}": "FakeObjectClass",    
+}
diff --git a/setup.py b/setup.py
index 94421655198..c9455eaa901 100644
--- a/setup.py
+++ b/setup.py
@@ -108,6 +108,7 @@ _deps = [
     "ftfy",
     "fugashi>=1.0",
     "GitPython<3.1.19",
+    "hf-doc-builder>=0.2.0",
     "huggingface-hub>=0.1.0,<1.0",
     "importlib_metadata",
     "ipadic>=1.0.0,<2.0",
@@ -283,12 +284,13 @@ extras["testing"] = (
         "rouge-score",
         "nltk",
         "GitPython",
+        "hf-doc-builder",
     )
     + extras["retrieval"]
     + extras["modelcreation"]
 )
 
-extras["quality"] = deps_list("black", "isort", "flake8", "GitPython")
+extras["quality"] = deps_list("black", "isort", "flake8", "GitPython", "hf-doc-builder")
 
 extras["all"] = (
     extras["tf"]
@@ -304,7 +306,7 @@ extras["all"] = (
 )
 
 # Might need to add doc-builder and some specific deps in the future
-extras["docs_specific"] = []
+extras["docs_specific"] = ["hf-doc-builder"]
 
 # "docs" needs "all" to resolve all the references
 extras["docs"] = extras["all"] + extras["docs_specific"]
diff --git a/src/transformers/commands/lfs.py b/src/transformers/commands/lfs.py
index 32c890af937..fe57943139c 100644
--- a/src/transformers/commands/lfs.py
+++ b/src/transformers/commands/lfs.py
@@ -9,8 +9,8 @@ Spec is: github.com/git-lfs/git-lfs/blob/master/docs/custom-transfers.md
 To launch debugger while developing:
 
 ``` [lfs "customtransfer.multipart"]
- path = /path/to/transformers/.env/bin/python args = -m debugpy --listen 5678 --wait-for-client
-/path/to/transformers/src/transformers/commands/transformers_cli.py lfs-multipart-upload ``` """
+path = /path/to/transformers/.env/bin/python args = -m debugpy --listen 5678 --wait-for-client
+/path/to/transformers/src/transformers/commands/transformers_cli.py lfs-multipart-upload ```"""
 
 import json
 import os
diff --git a/src/transformers/dependency_versions_table.py b/src/transformers/dependency_versions_table.py
index 2f78d38a410..2ba72f5b959 100644
--- a/src/transformers/dependency_versions_table.py
+++ b/src/transformers/dependency_versions_table.py
@@ -18,6 +18,7 @@ deps = {
     "ftfy": "ftfy",
     "fugashi": "fugashi>=1.0",
     "GitPython": "GitPython<3.1.19",
+    "hf-doc-builder": "hf-doc-builder>=0.2.0",
     "huggingface-hub": "huggingface-hub>=0.1.0,<1.0",
     "importlib_metadata": "importlib_metadata",
     "ipadic": "ipadic>=1.0.0,<2.0",
diff --git a/utils/check_copies.py b/utils/check_copies.py
index cf372437081..e823b866d2a 100644
--- a/utils/check_copies.py
+++ b/utils/check_copies.py
@@ -19,7 +19,7 @@ import os
 import re
 
 import black
-from style_doc import style_docstrings_in_code
+from doc_builder.style_doc import style_docstrings_in_code
 
 
 # All paths are set with the intent you should run this script from the root of the repo with the command
diff --git a/utils/style_doc.py b/utils/style_doc.py
deleted file mode 100644
index 4cc7215a45d..00000000000
--- a/utils/style_doc.py
+++ /dev/null
@@ -1,559 +0,0 @@
-# coding=utf-8
-# Copyright 2020 The HuggingFace Inc. team.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-"""Style utils for the .rst and the docstrings."""
-
-import argparse
-import os
-import re
-import warnings
-
-import black
-
-
-BLACK_AVOID_PATTERNS = {
-    "{processor_class}": "FakeProcessorClass",
-    "{model_class}": "FakeModelClass",
-    "{object_class}": "FakeObjectClass",
-}
-
-
-# Regexes
-# Re pattern that catches list introduction (with potential indent)
-_re_list = re.compile(r"^(\s*-\s+|\s*\*\s+|\s*\d+\.\s+)")
-# Re pattern that catches code block introduction (with potentinal indent)
-_re_code = re.compile(r"^(\s*)```(.*)$")
-# Re pattern that catches rst args blocks of the form `Parameters:`.
-_re_args = re.compile("^\s*(Args?|Arguments?|Params?|Parameters?):\s*$")
-# Re pattern that catches return blocks of the form `Return:`.
-_re_returns = re.compile("^\s*Returns?:\s*$")
-# Matches the special tag to ignore some paragraphs.
-_re_doc_ignore = re.compile(r"(\.\.|#)\s*docstyle-ignore")
-# Re pattern that matches <Tip>, </Tip> and <Tip warning={true}> blocks.
-_re_tip = re.compile("^\s*</?Tip(>|\s+warning={true}>)\s*$")
-
-DOCTEST_PROMPTS = [">>>", "..."]
-
-
-def is_empty_line(line):
-    return len(line) == 0 or line.isspace()
-
-
-def find_indent(line):
-    """
-    Returns the number of spaces that start a line indent.
-    """
-    search = re.search("^(\s*)(?:\S|$)", line)
-    if search is None:
-        return 0
-    return len(search.groups()[0])
-
-
-def parse_code_example(code_lines):
-    """
-    Parses a code example
-
-    Args:
-        code_lines (`List[str]`): The code lines to parse.
-        max_len (`int`): The maximum lengh per line.
-
-    Returns:
-        (List[`str`], List[`str`]): The list of code samples and the list of outputs.
-    """
-    has_doctest = code_lines[0][:3] in DOCTEST_PROMPTS
-
-    code_samples = []
-    outputs = []
-    in_code = True
-    current_bit = []
-
-    for line in code_lines:
-        if in_code and has_doctest and not is_empty_line(line) and line[:3] not in DOCTEST_PROMPTS:
-            code_sample = "\n".join(current_bit)
-            code_samples.append(code_sample.strip())
-            in_code = False
-            current_bit = []
-        elif not in_code and line[:3] in DOCTEST_PROMPTS:
-            output = "\n".join(current_bit)
-            outputs.append(output.strip())
-            in_code = True
-            current_bit = []
-
-        # Add the line without doctest prompt
-        if line[:3] in DOCTEST_PROMPTS:
-            line = line[4:]
-        current_bit.append(line)
-
-    # Add last sample
-    if in_code:
-        code_sample = "\n".join(current_bit)
-        code_samples.append(code_sample.strip())
-    else:
-        output = "\n".join(current_bit)
-        outputs.append(output.strip())
-
-    return code_samples, outputs
-
-
-def format_code_example(code: str, max_len: int, in_docstring: bool = False):
-    """
-    Format a code example using black. Will take into account the doctest syntax as well as any initial indentation in
-    the code provided.
-
-    Args:
-        code (`str`): The code example to format.
-        max_len (`int`): The maximum lengh per line.
-        in_docstring (`bool`, *optional*, defaults to `False`): Whether or not the code example is inside a docstring.
-
-    Returns:
-        `str`: The formatted code.
-    """
-    code_lines = code.split("\n")
-
-    # Find initial indent
-    idx = 0
-    while idx < len(code_lines) and is_empty_line(code_lines[idx]):
-        idx += 1
-    if idx >= len(code_lines):
-        return "", ""
-    indent = find_indent(code_lines[idx])
-
-    # Remove the initial indent for now, we will had it back after styling.
-    # Note that l[indent:] works for empty lines
-    code_lines = [l[indent:] for l in code_lines[idx:]]
-    has_doctest = code_lines[0][:3] in DOCTEST_PROMPTS
-
-    code_samples, outputs = parse_code_example(code_lines)
-
-    # Let's blackify the code! We put everything in one big text to go faster.
-    delimiter = "\n\n### New code sample ###\n"
-    full_code = delimiter.join(code_samples)
-    line_length = max_len - indent
-    if has_doctest:
-        line_length -= 4
-
-    for k, v in BLACK_AVOID_PATTERNS.items():
-        full_code = full_code.replace(k, v)
-    try:
-        mode = black.Mode(target_versions={black.TargetVersion.PY37}, line_length=line_length)
-        formatted_code = black.format_str(full_code, mode=mode)
-        error = ""
-    except Exception as e:
-        formatted_code = full_code
-        error = f"Code sample:\n{full_code}\n\nError message:\n{e}"
-
-    # Let's get back the formatted code samples
-    for k, v in BLACK_AVOID_PATTERNS.items():
-        formatted_code = formatted_code.replace(v, k)
-    # Triple quotes will mess docstrings.
-    if in_docstring:
-        formatted_code = formatted_code.replace('"""', "'''")
-
-    code_samples = formatted_code.split(delimiter)
-    # We can have one output less than code samples
-    if len(outputs) == len(code_samples) - 1:
-        outputs.append("")
-
-    formatted_lines = []
-    for code_sample, output in zip(code_samples, outputs):
-        # black may have added some new lines, we remove them
-        code_sample = code_sample.strip()
-        in_triple_quotes = False
-        in_decorator = False
-        for line in code_sample.strip().split("\n"):
-            if has_doctest and not is_empty_line(line):
-                prefix = (
-                    "... "
-                    if line.startswith(" ") or line in [")", "]", "}"] or in_triple_quotes or in_decorator
-                    else ">>> "
-                )
-            else:
-                prefix = ""
-            indent_str = "" if is_empty_line(line) else (" " * indent)
-            formatted_lines.append(indent_str + prefix + line)
-
-            if '"""' in line:
-                in_triple_quotes = not in_triple_quotes
-            if line.startswith(" "):
-                in_decorator = False
-            if line.startswith("@"):
-                in_decorator = True
-
-        formatted_lines.extend([" " * indent + line for line in output.split("\n")])
-        formatted_lines.append("")
-
-    result = "\n".join(formatted_lines)
-    return result.rstrip(), error
-
-
-def format_text(text, max_len, prefix="", min_indent=None):
-    """
-    Format a text in the biggest lines possible with the constraint of a maximum length and an indentation.
-
-    Args:
-        text (`str`): The text to format
-        max_len (`int`): The maximum length per line to use
-        prefix (`str`, *optional*, defaults to `""`): A prefix that will be added to the text.
-            The prefix doesn't count toward the indent (like a - introducing a list).
-        min_indent (`int`, *optional*): The minimum indent of the text.
-            If not set, will default to the length of the `prefix`.
-
-    Returns:
-        `str`: The formatted text.
-    """
-    text = re.sub(r"\s+", " ", text)
-    if min_indent is not None:
-        if len(prefix) < min_indent:
-            prefix = " " * (min_indent - len(prefix)) + prefix
-
-    indent = " " * len(prefix)
-    new_lines = []
-    words = text.split(" ")
-    current_line = f"{prefix}{words[0]}"
-    for word in words[1:]:
-        try_line = f"{current_line} {word}"
-        if len(try_line) > max_len:
-            new_lines.append(current_line)
-            current_line = f"{indent}{word}"
-        else:
-            current_line = try_line
-    new_lines.append(current_line)
-    return "\n".join(new_lines)
-
-
-def split_line_on_first_colon(line):
-    splits = line.split(":")
-    return splits[0], ":".join(splits[1:])
-
-
-def style_docstring(docstring, max_len):
-    """
-    Style a docstring by making sure there is no useless whitespace and the maximum horizontal space is used.
-
-    Args:
-        docstring (`str`): The docstring to style.
-        max_len (`int`): The maximum length of each line.
-
-    Returns:
-        `str`: The styled docstring
-    """
-    lines = docstring.split("\n")
-    new_lines = []
-
-    # Initialization
-    current_paragraph = None
-    current_indent = -1
-    in_code = False
-    param_indent = -1
-    prefix = ""
-    black_errors = []
-
-    # Special case for docstrings that begin with continuation of Args with no Args block.
-    idx = 0
-    while idx < len(lines) and is_empty_line(lines[idx]):
-        idx += 1
-    if (
-        len(lines[idx]) > 1
-        and lines[idx].rstrip().endswith(":")
-        and find_indent(lines[idx + 1]) > find_indent(lines[idx])
-    ):
-        param_indent = find_indent(lines[idx])
-
-    for idx, line in enumerate(lines):
-        # Doing all re searches once for the one we need to repeat.
-        list_search = _re_list.search(line)
-        code_search = _re_code.search(line)
-
-        # Are we starting a new paragraph?
-        # New indentation or new line:
-        new_paragraph = find_indent(line) != current_indent or is_empty_line(line)
-        # List item
-        new_paragraph = new_paragraph or list_search is not None
-        # Code block beginning
-        new_paragraph = new_paragraph or code_search is not None
-        # Beginning/end of tip
-        new_paragraph = new_paragraph or _re_tip.search(line)
-
-        # In this case, we treat the current paragraph
-        if not in_code and new_paragraph and current_paragraph is not None and len(current_paragraph) > 0:
-            paragraph = " ".join(current_paragraph)
-            new_lines.append(format_text(paragraph, max_len, prefix=prefix, min_indent=current_indent))
-            current_paragraph = None
-
-        if code_search is not None:
-            if not in_code:
-                current_paragraph = []
-                current_indent = len(code_search.groups()[0])
-                current_code = code_search.groups()[1]
-                prefix = ""
-                if current_indent < param_indent:
-                    param_indent = -1
-            else:
-                current_indent = -1
-                code = "\n".join(current_paragraph)
-                if current_code in ["py", "python"]:
-                    formatted_code, error = format_code_example(code, max_len, in_docstring=True)
-                    new_lines.append(formatted_code)
-                    if len(error) > 0:
-                        black_errors.append(error)
-                else:
-                    new_lines.append(code)
-                current_paragraph = None
-            new_lines.append(line)
-            in_code = not in_code
-
-        elif in_code:
-            current_paragraph.append(line)
-        elif is_empty_line(line):
-            current_paragraph = None
-            current_indent = -1
-            prefix = ""
-            new_lines.append(line)
-        elif list_search is not None:
-            prefix = list_search.groups()[0]
-            current_indent = len(prefix)
-            current_paragraph = [line[current_indent:]]
-        elif _re_args.search(line):
-            new_lines.append(line)
-            param_indent = find_indent(lines[idx + 1])
-        elif _re_tip.search(line):
-            # Add a new line before if not present
-            if not is_empty_line(new_lines[-1]):
-                new_lines.append("")
-            new_lines.append(line)
-            # Add a new line after if not present
-            if idx < len(lines) - 1 and not is_empty_line(lines[idx + 1]):
-                new_lines.append("")
-        elif current_paragraph is None or find_indent(line) != current_indent:
-            indent = find_indent(line)
-            # Special behavior for parameters intros.
-            if indent == param_indent:
-                # Special rules for some docstring where the Returns blocks has the same indent as the parameters.
-                if _re_returns.search(line) is not None:
-                    param_indent = -1
-                    new_lines.append(line)
-                elif len(line) < max_len:
-                    new_lines.append(line)
-                else:
-                    intro, description = split_line_on_first_colon(line)
-                    new_lines.append(intro + ":")
-                    if len(description) != 0:
-                        if find_indent(lines[idx + 1]) > indent:
-                            current_indent = find_indent(lines[idx + 1])
-                        else:
-                            current_indent = indent + 4
-                        current_paragraph = [description.strip()]
-                        prefix = ""
-            else:
-                # Check if we have exited the parameter block
-                if indent < param_indent:
-                    param_indent = -1
-
-                current_paragraph = [line.strip()]
-                current_indent = find_indent(line)
-                prefix = ""
-        elif current_paragraph is not None:
-            current_paragraph.append(line.lstrip())
-
-    if current_paragraph is not None and len(current_paragraph) > 0:
-        paragraph = " ".join(current_paragraph)
-        new_lines.append(format_text(paragraph, max_len, prefix=prefix, min_indent=current_indent))
-
-    return "\n".join(new_lines), "\n\n".join(black_errors)
-
-
-def style_docstrings_in_code(code, max_len=119):
-    """
-    Style all docstrings in some code.
-
-    Args:
-        code (`str`): The code in which we want to style the docstrings.
-        max_len (`int`): The maximum number of characters per line.
-
-    Returns:
-        `Tuple[str, str]`: A tuple with the clean code and the black errors (if any)
-    """
-    # fmt: off
-    splits = code.split('\"\"\"')
-    splits = [
-        (s if i % 2 == 0 or _re_doc_ignore.search(splits[i - 1]) is not None else style_docstring(s, max_len=max_len))
-        for i, s in enumerate(splits)
-    ]
-    black_errors = "\n\n".join([s[1] for s in splits if isinstance(s, tuple) and len(s[1]) > 0])
-    splits = [s[0] if isinstance(s, tuple) else s for s in splits]
-    clean_code = '\"\"\"'.join(splits)
-    # fmt: on
-
-    return clean_code, black_errors
-
-
-def style_file_docstrings(code_file, max_len=119, check_only=False):
-    """
-    Style all docstrings in a given file.
-
-    Args:
-        code_file (`str` or `os.PathLike`): The file in which we want to style the docstring.
-        max_len (`int`): The maximum number of characters per line.
-        check_only (`bool`, *optional*, defaults to `False`):
-            Whether to restyle file or just check if they should be restyled.
-
-    Returns:
-        `bool`: Whether or not the file was or should be restyled.
-    """
-    with open(code_file, "r", encoding="utf-8", newline="\n") as f:
-        code = f.read()
-
-    clean_code, black_errors = style_docstrings_in_code(code, max_len=max_len)
-
-    diff = clean_code != code
-    if not check_only and diff:
-        print(f"Overwriting content of {code_file}.")
-        with open(code_file, "w", encoding="utf-8", newline="\n") as f:
-            f.write(clean_code)
-
-    return diff, black_errors
-
-
-def style_mdx_file(mdx_file, max_len=119, check_only=False):
-    """
-    Style a MDX file by formatting all Python code samples.
-
-    Args:
-        mdx_file (`str` or `os.PathLike`): The file in which we want to style the examples.
-        max_len (`int`): The maximum number of characters per line.
-        check_only (`bool`, *optional*, defaults to `False`):
-            Whether to restyle file or just check if they should be restyled.
-
-    Returns:
-        `bool`: Whether or not the file was or should be restyled.
-    """
-    with open(mdx_file, "r", encoding="utf-8", newline="\n") as f:
-        content = f.read()
-
-    lines = content.split("\n")
-    current_code = []
-    current_language = ""
-    in_code = False
-    new_lines = []
-    black_errors = []
-
-    for line in lines:
-        if _re_code.search(line) is not None:
-            in_code = not in_code
-            if in_code:
-                current_language = _re_code.search(line).groups()[1]
-                current_code = []
-            else:
-                code = "\n".join(current_code)
-                if current_language in ["py", "python"]:
-                    code, error = format_code_example(code, max_len)
-                    if len(error) > 0:
-                        black_errors.append(error)
-                new_lines.append(code)
-
-            new_lines.append(line)
-        elif in_code:
-            current_code.append(line)
-        else:
-            new_lines.append(line)
-
-    if in_code:
-        raise ValueError(f"There was a problem when styling {mdx_file}. A code block is opened without being closed.")
-
-    clean_content = "\n".join(new_lines)
-    diff = clean_content != content
-    if not check_only and diff:
-        print(f"Overwriting content of {mdx_file}.")
-        with open(mdx_file, "w", encoding="utf-8", newline="\n") as f:
-            f.write(clean_content)
-
-    return diff, "\n\n".join(black_errors)
-
-
-def style_doc_files(*files, max_len=119, check_only=False):
-    """
-    Applies doc styling or checks everything is correct in a list of files.
-
-    Args:
-        files (several `str` or `os.PathLike`): The files to treat.
-        max_len (`int`): The maximum number of characters per line.
-        check_only (`bool`, *optional*, defaults to `False`):
-            Whether to restyle file or just check if they should be restyled.
-
-    Returns:
-        List[`str`]: The list of files changed or that should be restyled.
-    """
-    changed = []
-    black_errors = []
-    for file in files:
-        # Treat folders
-        if os.path.isdir(file):
-            files = [os.path.join(file, f) for f in os.listdir(file)]
-            files = [f for f in files if os.path.isdir(f) or f.endswith(".mdx") or f.endswith(".py")]
-            changed += style_doc_files(*files, max_len=max_len, check_only=check_only)
-        # Treat mdx
-        elif file.endswith(".mdx"):
-            try:
-                diff, black_error = style_mdx_file(file, max_len=max_len, check_only=check_only)
-                if diff:
-                    changed.append(file)
-                if len(black_error) > 0:
-                    black_errors.append(
-                        f"There was a problem while formatting an example in {file} with black:\m{black_error}"
-                    )
-            except Exception:
-                print(f"There is a problem in {file}.")
-                raise
-        # Treat python files
-        elif file.endswith(".py"):
-            try:
-                diff, black_error = style_file_docstrings(file, max_len=max_len, check_only=check_only)
-                if diff:
-                    changed.append(file)
-                if len(black_error) > 0:
-                    black_errors.append(
-                        f"There was a problem while formatting an example in {file} with black:\m{black_error}"
-                    )
-            except Exception:
-                print(f"There is a problem in {file}.")
-                raise
-        else:
-            warnings.warn(f"Ignoring {file} because it's not a py or an mdx file or a folder.")
-    if len(black_errors) > 0:
-        black_message = "\n\n".join(black_errors)
-        raise ValueError(
-            "Some code examples can't be interpreted by black, which means they aren't regular python:\n\n"
-            + black_message
-            + "\n\nMake sure to fix the corresponding docstring or doc file, or remove the py/python after ``` if it "
-            + "was not supposed to be a Python code sample."
-        )
-    return changed
-
-
-def main(*files, max_len=119, check_only=False):
-    changed = style_doc_files(*files, max_len=max_len, check_only=check_only)
-    if check_only and len(changed) > 0:
-        raise ValueError(f"{len(changed)} files should be restyled!")
-    elif len(changed) > 0:
-        print(f"Cleaned {len(changed)} files!")
-
-
-if __name__ == "__main__":
-    parser = argparse.ArgumentParser()
-    parser.add_argument("files", nargs="+", help="The file(s) or folder(s) to restyle.")
-    parser.add_argument("--max_len", type=int, help="The maximum length of lines.")
-    parser.add_argument("--check_only", action="store_true", help="Whether to only check and not fix styling issues.")
-    args = parser.parse_args()
-
-    main(*args.files, max_len=args.max_len, check_only=args.check_only)