input: Write a python function to find indices of two elements in the array that sum up to a given number.
  assert sumIndices([3, 5, 7, 10], 10) == (0, 2)
  assert sumIndices([1, 2, 3, 4, 5], 9) == (3, 4)
  assert sumIndices([2, 7, 11, 15], 9) == (0, 1)
  assert sumIndices([1, 3, 4, 2], 5) == (1, 2)
output: def sumIndices(arr, target):
      index_map = {}
      for i, num in enumerate(arr):
          complement = target - num
          if complement in index_map:
              return (index_map[complement], i)
          index_map[num] = i