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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def send(sender_instance):
 """Send a transactional email using SendInBlue API. Site: https://www.sendinblue.com API: https://apidocs.sendinblue.com/ """

    m = Mailin(
        "https://api.sendinblue.com/v2.0",
        sender_instance._kwargs.get("api_key")
    )
    data = {
        "to": email_list_to_email_dict(sender_instance._recipient_list),
        "cc": email_list_to_email_dict(sender_instance._cc),
        "bcc": email_list_to_email_dict(sender_instance._bcc),
        "from": email_address_to_list(sender_instance._from_email),
        "subject": sender_instance._subject,
    }
    if sender_instance._template.is_html:
        data.update({
            "html": sender_instance._message,
            "headers": {"Content-Type": "text/html; charset=utf-8"}
        })
    else:
        data.update({"text": sender_instance._message})
    if "attachments" in sender_instance._kwargs:
        data["attachment"] = {}
        for attachment in sender_instance._kwargs["attachments"]:
            data["attachment"][attachment[0]] = base64.b64encode(attachment[1])
    result = m.send_email(data)
    if result["code"] != "success":
        raise SendInBlueError(result["message"])