-`send_ms`, which only has its implementation type (**self**) as argument and returns an option:
- This function must return `None` if the content of the message is either **empty** or contains the word **stupid**. Otherwise it returns the content of the message.
- receives as parameters the reference to the structure `Message`
- and returns a tuple, containing a `bool` and a `string`:
- This function will execute the function `send_ms` and if the result of the option is `None`, it should return (false, "ERROR: illegal").Otherwise it returns `true` and the content of the message sent.