input: Write a function to remove all duplicates from a given list of numbers and return the list with unique elements only. The input list can contain any integers and can be empty.
  assert deleteDuplicates([1, 2, 3, 1, 2, 3, 4, 5])==[1, 2, 3, 4, 5]
  assert deleteDuplicates([1, 1, 1, 1])==[1]
  assert deleteDuplicates([5, 4, 3, 2, 1])==[5, 4, 3, 2, 1]
  assert deleteDuplicates([])==[]
output: def deleteDuplicates(nums):
      return list(set(nums))