input: Write a function to create a Python generator that returns numbers from a given list. If the list is empty, the generator should not yield anything.
  assert list(list_generator([1, 3, 5, 7, 9])) == [1, 3, 5, 7, 9]
  assert list(list_generator([2, 4, 6, 8])) == [2, 4, 6, 8]
  assert list(list_generator([])) == []
output: def list_generator(lst):
      for num in lst:
          yield num