input: Write a python function to convert a string to hexadecimal and back.
  assert to_hex_and_back('hello') == 'hello'
  assert to_hex_and_back('world') == 'world'
  assert to_hex_and_back('Python') == 'Python'
output: def to_hex_and_back(s: str) -> str:
      # Convert string to hexadecimal
      hex_string = s.encode('utf-8').hex()
      
      # Convert hexadecimal back to string
      original_string = bytes.fromhex(hex_string).decode('utf-8')
      
      return original_string