input: Write a python function to encode a list of strings to UTF-8.
  assert encode_list_of_strings(["hello", "world", "how", "are", "you"]) == [b'hello', b'world', b'how', b'are', b'you']
  assert encode_list_of_strings(["apple", "banana", "cherry"]) == [b'apple', b'banana', b'cherry']
  assert encode_list_of_strings([""]) == [b'']
  assert encode_list_of_strings([]) == []
output: def encode_list_of_strings(strings):
      return [s.encode('utf-8') for s in strings]