diff --git a/physics/newtons_second_law_of_motion.py b/physics/newtons_second_law_of_motion.py
index 53fab6ce78b9..4149e2494f31 100644
--- a/physics/newtons_second_law_of_motion.py
+++ b/physics/newtons_second_law_of_motion.py
@@ -1,18 +1,22 @@
-"""
-Description :
-Newton's second law of motion pertains to the behavior of objects for which
-all existing forces are not balanced.
-The second law states that the acceleration of an object is dependent upon two variables
-- the net force acting upon the object and the mass of the object.
-The acceleration of an object depends directly
-upon the net force acting upon the object,
-and inversely upon the mass of the object.
-As the force acting upon an object is increased,
-the acceleration of the object is increased.
-As the mass of an object is increased, the acceleration of the object is decreased.
+r"""
+Description:
+    Newton's second law of motion pertains to the behavior of objects for which
+    all existing forces are not balanced.
+    The second law states that the acceleration of an object is dependent upon
+    two variables - the net force acting upon the object and the mass of the object.
+    The acceleration of an object depends directly
+    upon the net force acting upon the object,
+    and inversely upon the mass of the object.
+    As the force acting upon an object is increased,
+    the acceleration of the object is increased.
+    As the mass of an object is increased, the acceleration of the object is decreased.
+
 Source: https://www.physicsclassroom.com/class/newtlaws/Lesson-3/Newton-s-Second-Law
-Formulation: Fnet = m • a
-Diagrammatic Explanation:
+
+Formulation: F_net = m • a
+
+Diagrammatic Explanation::
+
               Forces are unbalanced
                         |
                         |
@@ -26,35 +30,42 @@
                     /        \
                    /          \
                   /            \
-        __________________   ____ ________________
-        |The acceleration |  |The acceleration   |
-        |depends directly |  |depends inversely  |
-        |on the net Force |  |upon the object's  |
-        |_________________|  |mass_______________|
-Units:
-1 Newton = 1 kg X meters / (seconds^2)
+    __________________      ____________________
+   | The acceleration |    | The acceleration   |
+   | depends directly |    | depends inversely  |
+   | on the net force |    | upon the object's  |
+   |                  |    | mass               |
+   |__________________|    |____________________|
+
+Units: 1 Newton = 1 kg • meters/seconds^2
+
 How to use?
-Inputs:
-    ___________________________________________________
-   |Name         | Units                   | Type      |
-   |-------------|-------------------------|-----------|
-   |mass         | (in kgs)                | float     |
-   |-------------|-------------------------|-----------|
-   |acceleration | (in meters/(seconds^2)) | float     |
-   |_____________|_________________________|___________|
-
-Output:
-    ___________________________________________________
-   |Name         | Units                   | Type      |
-   |-------------|-------------------------|-----------|
-   |force        | (in Newtons)            | float     |
-   |_____________|_________________________|___________|
+
+Inputs::
+
+    ______________ _____________________ ___________
+   | Name         | Units               | Type      |
+   |--------------|---------------------|-----------|
+   | mass         | in kgs              | float     |
+   |--------------|---------------------|-----------|
+   | acceleration | in meters/seconds^2 | float     |
+   |______________|_____________________|___________|
+
+Output::
+
+    ______________ _______________________ ___________
+   | Name         | Units                 | Type      |
+   |--------------|-----------------------|-----------|
+   | force        | in Newtons            | float     |
+   |______________|_______________________|___________|
 
 """
 
 
 def newtons_second_law_of_motion(mass: float, acceleration: float) -> float:
     """
+    Calculates force from `mass` and `acceleration`
+
     >>> newtons_second_law_of_motion(10, 10)
     100
     >>> newtons_second_law_of_motion(2.0, 1)
diff --git a/requirements.txt b/requirements.txt
index 4cc83f44987d..b104505e01bc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 beautifulsoup4
-fake_useragent
+fake-useragent
 imageio
 keras
 lxml
@@ -11,7 +11,7 @@ pillow
 requests
 rich
 scikit-learn
-sphinx_pyproject
+sphinx-pyproject
 statsmodels
 sympy
 tweepy
diff --git a/strings/join.py b/strings/join.py
index 5c02f65a20ce..cdcc3a1377f4 100644
--- a/strings/join.py
+++ b/strings/join.py
@@ -24,6 +24,8 @@ def join(separator: str, separated: list[str]) -> str:
     'a'
     >>> join(" ", ["You", "are", "amazing!"])
     'You are amazing!'
+    >>> join(",", ["", "", ""])
+    ',,'
 
     This example should raise an
     exception for non-string elements:
@@ -37,15 +39,33 @@ def join(separator: str, separated: list[str]) -> str:
     'apple-banana-cherry'
     """
 
-    joined = ""
+    # Check that all elements are strings
     for word_or_phrase in separated:
+        # If the element is not a string, raise an exception
         if not isinstance(word_or_phrase, str):
             raise Exception("join() accepts only strings")
+
+    joined: str = ""
+    """
+    The last element of the list is not followed by the separator.
+    So, we need to iterate through the list and join each element
+    with the separator except the last element.
+    """
+    last_index: int = len(separated) - 1
+    """
+    Iterate through the list and join each element with the separator.
+    Except the last element, all other elements are followed by the separator.
+    """
+    for word_or_phrase in separated[:last_index]:
+        # join the element with the separator.
         joined += word_or_phrase + separator
 
-    # Remove the trailing separator
-    # by stripping it from the result
-    return joined.strip(separator)
+    # If the list is not empty, join the last element.
+    if separated != []:
+        joined += separated[last_index]
+
+    # Return the joined string.
+    return joined
 
 
 if __name__ == "__main__":
diff --git a/strings/split.py b/strings/split.py
index b62b86d2401f..ed194ec69c2f 100644
--- a/strings/split.py
+++ b/strings/split.py
@@ -14,6 +14,9 @@ def split(string: str, separator: str = " ") -> list:
 
     >>> split("12:43:39",separator = ":")
     ['12', '43', '39']
+
+    >>> split(";abbb;;c;", separator=';')
+    ['', 'abbb', '', 'c', '']
     """
 
     split_words = []
@@ -23,7 +26,7 @@ def split(string: str, separator: str = " ") -> list:
         if char == separator:
             split_words.append(string[last_index:index])
             last_index = index + 1
-        elif index + 1 == len(string):
+        if index + 1 == len(string):
             split_words.append(string[last_index : index + 1])
     return split_words