Data Processing and Bug Fixing Task

Given an array of integers, implement a function to calculate the sum of all elements in the array. The task consists of the following three parts: Part 1 Implement a function calculate_sum(arr: List[int]) -> int, which takes an array of integers as input and returns the sum of all elements. Part 2 Write test cases for the above function to ensure it works correctly for various inputs. Test cases should cover positive numbers, negative numbers, and empty array scenarios. Part 3 Extend the function to exclude duplicate elements' contribution when calculating the total sum. For example, for array [1, 2, 2, 3], it should return 6 instead of 8. Example Input [1, 2, 3]