diff --git a/dynamic_programming/longest_sub_array.py b/dynamic_programming/longest_sub_array.py
index b477acf61e66..43c3d88c8305 100644
--- a/dynamic_programming/longest_sub_array.py
+++ b/dynamic_programming/longest_sub_array.py
@@ -16,6 +16,21 @@ def __init__(self, arr):
         self.array = arr.split(",")
 
     def solve_sub_array(self):
+        """
+        Solve the maximum subarray sum problem using dynamic programming.
+        Returns:
+        int: The maximum subarray sum.
+        Examples:
+        >>> subarray = SubArray("1, 2, 3, -2, 5")
+        >>> subarray.solve_sub_array()
+        9
+        >>> subarray = SubArray("-2, 1, -3, 4, -1, 2, 1, -5, 4")
+        >>> subarray.solve_sub_array()
+        6
+        >>> subarray = SubArray("1")
+        >>> subarray.solve_sub_array()
+        1
+        """
         rear = [int(self.array[0])] * len(self.array)
         sum_value = [int(self.array[0])] * len(self.array)
         for i in range(1, len(self.array)):