input: Write a python function to convert all elements of a list to strings.
  assert convert_to_strings([1, 2, 3]) == ['1', '2', '3']
  assert convert_to_strings([10, 20, 30]) == ['10', '20', '30']
  assert convert_to_strings(['a', 'b', 'c']) == ['a', 'b', 'c']
output: def convert_to_strings(lst):
      return [str(element) for element in lst]