def send_invoice_email(self, invoice_id, email_dict):
        """
        Sends an invoice by email
        If you want to send your email to more than one persons do:
        'recipients': {'to': ['bykof@me.com', 'mbykovski@seibert-media.net']}}

        :param invoice_id: the invoice id
        :param email_dict: the email dict
        :return dict
        """
        return self._create_post_request(
            resource=INVOICES,
            billomat_id=invoice_id,
            send_data=email_dict,
            command=EMAIL,
        )
Sends an invoice by email
        If you want to send your email to more than one persons do:
        'recipients': {'to': ['bykof@me.com', 'mbykovski@seibert-media.net']}}

        :param invoice_id: the invoice id
        :param email_dict: the email dict
        :return dict