# Problem Description
This appears to be a problem about calculating a specific sum in a 3x3 matrix, but the complete requirements aren't clear from the function signature alone. The image suggests we need to calculate the sum of elements along two diagonal paths marked by arrows in each matrix case.

# Visual Facts
1. Each case shows a 3x3 matrix with integers
2. Each matrix has two diagonal arrow lines crossing through it
3. Three example cases are provided with their sums:
   - Case 1: Sum = 25
   - Case 2: Sum = 19
   - Case 3: Sum = 16
4. The diagonal arrows are oriented from top-left to bottom-right and from top-right to bottom left
5. The diagonal line passes through exactly 5 cells in each matrix

# Visual Patterns
1. The sum in each case corresponds to the numbers along the diagonal path:
   - Case 1: 1 + 5 + 9 + 3 + 7 = 25
   - Case 2: 5 + 0 + 1 + 5 + 8 = 19
   - Case 3: 2 + 1 + 7 + 3 + 3 = 16

2. The first diagonal always follows the pattern:
   - Starts at top-right element (position [0][0])
   - Goes through middle element (position [1][1])
   - Ends at bottom-left element (position [2][2])

3. The second diagonal always follows the pattern:
   - Starts at top-right element (position [0][2])
   - Goes through middle element (position [1][1])
   - Ends at bottom-left element (position [2][0])

4. This is specifically the diagonal pattern, but only these five positions are included in the sum


# Solution
from typing import List

def solution(matrix: List[List[int]]) -> int:
    """
    Calculate the sum of the elements in the matrix.

    Parameters:
        matrix (List[List[int]]): A 3x3 integer matrix.        

    Returns:
        int: The sum of the elements in the matrix.      
    """
    return matrix[0][0] + matrix[1][1] + matrix[2][2] + matrix[0][2] + matrix[2][0]


# Test Script
def test():
    test_cases = [
        ([[1, 2, 3], [4, 5, 6], [7, 8, 9]], 25),
        ([[4, 4, 2], [1, 8, 6], [5, 3, 5]], 24),
        ([[4, 4, 1], [1, 3, 3], [2, 3, 5]], 15),
        ([[1, 0, 0], [2, 8, 6], [5, 4, 2]], 16),
        ([[3, 4, 5], [6, 1, 3], [2, 2, 1]], 12),
        ([[7, 1, 1], [2, 4, 6], [1, 3, 5]], 18),
        ([[1, 4, 0], [1, 0, 6], [0, 3, 3]], 4),
        ([[1, 3, 2], [3, 2, 6], [2, 2, 1]], 8),
        ([[1, 1, 1], [1, 1, 1], [2, 3, 4]], 9),
        ([[2, 1, 0], [-1, -8, -6], [-5, -3, -5]], -16),
    ]

    for matrix, expected_output in test_cases:
        try:
            output = solution(matrix)
        except Exception as e:
            error_message = (
                f"An exception occurred while running the test case:\n"
                f"`matrix`: {matrix}\n\n"
                f"Exception: '{str(e)}'"
            )
            assert False, error_message

        if output != expected_output:
            error_message = (
                f"The following Test Case failed:\n"
                f"`matrix`: {matrix}\n\n"
                f"Actual Output: {output}\n"
                f"Expected Output: {expected_output}"
            )
            assert False, error_message

test()