diff --git a/docs/requirements.txt b/docs/requirements.txt
index 98d2c6f7..8f290cb6 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,6 @@
-Sphinx
+Sphinx==4.5.0
+docutils<0.17
+sphinx-rtd-theme>=0.5.2
 sphinx-gallery
 sphinxcontrib-phpdomain
 sphinx-autoapi
@@ -7,4 +9,3 @@ DoubleML
 pyts
 dowhy
 numpy<1.23
-Jinja2<3.1
diff --git a/python/abess/linear.py b/python/abess/linear.py
index c6ac7b72..4b91558f 100644
--- a/python/abess/linear.py
+++ b/python/abess/linear.py
@@ -15,10 +15,25 @@
 def fix_docs(cls):
     # This function is to inherit the docstring from base class
     # and avoid unnecessary duplications on description.
-    index = cls.__doc__.find("Examples\n    --------\n")
-    if index != -1:
-        cls.__doc__ = cls.__doc__[:index] + \
-            cls.__bases__[0].__doc__ + cls.__doc__[index:]
+    title_index = cls.__doc__.find("Parameters\n    ----------")
+    more_para_index = cls.__doc__.find("Examples\n    --------")
+    base_para_index = cls.__bases__[0].__doc__.find(
+        "Attributes\n    ----------")
+    if title_index == -1:
+        title_index = 0
+    if more_para_index == -1:
+        more_para_index = len(cls.__doc__) - 1
+    # class title
+    full_doc = cls.__doc__[:title_index]
+    # class paras
+    full_doc = (full_doc +
+                cls.__bases__[0].__doc__[:base_para_index] +
+                cls.__doc__[title_index:more_para_index])
+    # more info
+    full_doc = (full_doc +
+                cls.__doc__[more_para_index:] +
+                cls.__bases__[0].__doc__[base_para_index:])
+    cls.__doc__ = full_doc
     return cls