diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index eba8a7be2..eb18b4638 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -54,7 +54,6 @@ about: A template PR for code review with a checklist
 
 - [ ] The function's name describes it's behavior
 - [ ] The function's name matches the file name
-  - _It's ok to have extra helper functions if necessary, like with mergesort_
 - [ ] The function has correct type annotations
 - [ ] The function is not called at the top level of the function file 
   - _Recursive solutions **can** call the function from **inside** the function body_
@@ -69,7 +68,7 @@ about: A template PR for code review with a checklist
 
 ### Don'ts
 
-- [ ] The function's strategy _is not_ described in any docstrings or tests
+- [ ] The function's strategy _is not_ described in the documentation
 - [ ] Comments explain the _strategy_, **not** the _implementation_
 - [ ] The function _does not_ have more comments than code
   - If it does, consider finding a new strategy or a simpler implementation
diff --git a/collaboration/retrospective.md b/collaboration/retrospective.md
new file mode 100644
index 000000000..8b0930e22
--- /dev/null
+++ b/collaboration/retrospective.md
@@ -0,0 +1,75 @@
+<!-- this template is for inspiration, feel free to change it however you like! -->
+
+# Retrospective: Group 18 - Collaborative Work Activity
+
+## Stop Doing
+
+- **Inefficient Coordination:** Stop relying on informal communication
+  methods that cause misunderstandings or delays.
+
+- **Overloading Tasks:** Avoid taking on excessive responsibilities
+  without proper delegation or prioritization.
+
+- **Passive Participation:** Stop being a silent participant in discussions;
+  ensure to actively contribute to conversations.
+
+## Continue Doing
+
+- **Effective Teamwork:** Continue fostering collaboration by sharing ideas
+  openly and respecting diverse perspectives.
+
+- **Timely Updates:** Maintain a habit of providing timely progress updates
+  to keep the team aligned.
+
+- **Using Tools:** Keep leveraging collaborative tools
+  (e.g., shared documents, project management software) to enhance productivity.
+
+## Start Doing
+
+- **Structured Planning:** Begin creating more detailed action plans with
+  clear milestones and deadlines.
+
+- **Feedback Loops:** Start implementing regular feedback sessions to
+  evaluate progress and address challenges early.
+
+- **Skill Development:** Focus on improving specific skills related
+  to collaborative work and presentation to contribute more effectively.
+
+## Lessons Learned
+
+- Effective communication is crucial to avoid duplication of efforts and ensure alignment.
+
+- Clear roles and responsibilities significantly enhance team productivity.
+
+- Flexibility in strategy allows for better adaptation to unforeseen challenges.
+
+- Regular check-ins help maintain momentum and ensure accountability.
+
+______________________________________________________________________
+
+## Strategy vs. Board
+
+### What parts of your plan went as expected?
+
+- Collaboration tools were effectively utilized to
+  share resources and coordinate tasks.
+
+- The team successfully met initial deadlines for project deliverables.
+
+- Team members demonstrated a willingness to support each other when challenges arose.
+
+### What parts of your plan did not work out?
+
+- Some tasks were delayed due to unclear task ownership.
+
+- Miscommunication led to redundant efforts in certain areas.
+
+- Time zone differences caused occasional scheduling conflicts.
+
+### Did you need to add things that weren't in your strategy?
+
+- Yes, we added weekly synchronization meetings to
+  address miscommunications and ensure alignment.
+
+- Included additional training sessions for team members to
+  improve tool usage efficiency.
diff --git a/solutions/cumulative_sum.py b/solutions/cumulative_sum.py
index 2e77fb9d0..5c246f54a 100644
--- a/solutions/cumulative_sum.py
+++ b/solutions/cumulative_sum.py
@@ -13,7 +13,7 @@
     - cumulative_sum(numbers: list) -> list:
         Computes and returns a list of cumulative sums from the input list.
 
-Author: Falaq Youniss
+Author: Falaq Youniss.
 Date: 29/12/2024
 """
 
@@ -44,9 +44,9 @@ def cumulative_sum(numbers: list) -> list:
     # Validate input
     assert numbers is not None, "Input cannot be None."
     assert isinstance(numbers, list), "Input must be a list of numeric values."
-    assert all(
-        isinstance(num, (int, float)) for num in numbers
-    ), "All elements in the list must be numeric."
+    assert all(isinstance(num, (int, float)) for num in numbers), (
+        "All elements in the list must be numeric."
+    )
     # Compute cumulative sums
     cumulative_list = []
     current_sum = 0