input: Write a python function to find the product of distinct elements in a given array.
  assert unique_product([10, 20, 30, 40, 20, 50, 60, 40]) == 720000000
  assert unique_product([1, 2, 3, 1,]) == 6
  assert unique_product([7, 8, 9, 0, 1, 1]) == 0
output: def unique_product(arr):
      unique_elements = set(arr)
      product = 1
      for num in unique_elements:
          product *= num
      return product