diff --git a/solutions/sum_of_list.py b/solutions/sum_of_list.py
new file mode 100644
index 000000000..f99079335
--- /dev/null
+++ b/solutions/sum_of_list.py
@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+
+# Write a function that takes a list and returns the sum of that list.
+
+"""
+A module for getting the sum of numbers in a list
+
+Module contents:
+    sum_of_list: returns the sum of numbers in a list.
+
+Created on 02/01/2025
+@author: Ndubuisi Agbo
+"""
+
+
+def sum_of_list(numbers: list) -> int | float:
+    """Gives the sum of the elements in a list.
+
+    Parameters:
+        numbers (list): the list of numbers to sum.
+
+    Returns:
+        int or float: the sum of the numbers in the list.
+
+    Raises:
+        AssertionError: if the list contains a non-numeric element.
+        AssertionError: if the argument is not a list.
+
+    >>> sum_of_list([3,6,9])
+    18
+
+    >>> sum_of_list([4.2, 6.9, 7.1])
+    18.2
+
+    >>> sum_of_list([8, 3.8, 1, 9])
+    21.8
+    """
+
+    assert isinstance(numbers, list), "numbers must be a list"
+
+    # checks that all the elements in the list are a number
+    for num in numbers:
+        assert isinstance(num, int | float)
+
+    return sum(numbers)
diff --git a/solutions/tests/test_sum_of_list.py b/solutions/tests/test_sum_of_list.py
new file mode 100644
index 000000000..c62ea3c7b
--- /dev/null
+++ b/solutions/tests/test_sum_of_list.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+"""
+A module for testing the sum_of_list function.
+This module tests the following categories:
+    - Standard cases
+    - Edge cases
+    - Defensive tests
+
+Created on 02/01/2025
+@author: Ndubuisi Agbo
+"""
+
+import unittest
+from ..sum_of_list import sum_of_list
+
+
+class TestSumOfList(unittest.TestCase):
+    """This module tests the sum_of_list function"""
+
+    # Standard test cases
+    def test_list_of_integers(self):
+        """It should return the sum of the list"""
+        self.assertEqual(sum_of_list([3, 6, 9]), 18)
+
+    def test_list_of_floats(self):
+        """It should return the sum of the list"""
+        self.assertEqual(sum_of_list([4.2, 6.9, 7.1]), 18.2)
+
+    def test_list_of_mixed_number(self):
+        """It should return the sum of the list"""
+        self.assertEqual(sum_of_list([8, 3.8, 1, 9]), 21.8)
+
+    # Edge cases
+    def test_empty_list(self):
+        """Returns zero when an empty list is passed"""
+        self.assertEqual(sum_of_list([]), 0)
+
+    def test_single_element(self):
+        """It should return the element in the list"""
+        self.assertEqual(sum_of_list([7]), 7)
+
+    # Defensive tests
+    def test_list_of_strings(self):
+        """Raises AssertionError when a list containing a string is passed"""
+        with self.assertRaises(AssertionError):
+            sum_of_list(["3", "9", "6"])
+
+    def test_non_list(self):
+        """Raises AssertionError when the argument is not a list"""
+        with self.assertRaises(AssertionError):
+            sum_of_list("two")
+
+
+if __name__ == "__main__":
+    unittest.main()