Skipping empty values

[madbob]

This is intended to simplify set of multiple values, such as in:

$e->setValues('DatiTrasmissione', [
    // ...
    'PECDestinatario' => $customer->sdi_code == '0000000' ? $customer->pec : null,
    // ...
]);

[aded]

This is intended to simplify set of multiple values, such as in:
(...)

Hi madbob, thanks for your PR. I'll take a look at the package in few days and will update the code soon - need to improve it :-)