input: Write a python function to populate a dictionary where the keys and values are the same from a given list.
  assert populateDict([1, 2, 3, 4, 5]) == {1: 1, 2: 2, 3: 3, 4: 4, 5: 5}
  assert populateDict(['a', 'b', 'c']) == {'a': 'a', 'b': 'b', 'c': 'c'}
  assert populateDict([]) == {}
output: def populateDict(lst):
      return {x: x for x in lst}