input: Write a python function to log a message with a timestamp.
  assert log('Test message') is None # Check that the function does not return any value
  assert isinstance(log('Another message'), type(None)) # Check the return type
  assert 'Logging Message' in log('Logging Message') # Validate the output contains the log message
output: def log(message):
      from datetime import datetime
      timestamp = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
      log_message = f"{timestamp} - {message}"
      print(log_message)