Simple, full-featured sendgrid email sending

an_email.py

from send import send_email

def main(sandbox_mode=True):
    send_email(
        to_emails=["person1@example.com"],
        from_email="my@email",
        subject="Catchup",
        html_content="Hello Umm Greg Universe,<br/>How are you?",
        cc_emails=["an-email"],
        reply_to=("my@example.com", "Me"),
        sandbox_mode=sandbox_mode,
    )
if __name__ == "__main__":
    main(sandbox_mode=True)

send.py

import os
import sendgrid

from sendgrid.helpers.mail import (
    Content,
    Email,
    Mail,
    MailSettings,
    Personalization,
    ReplyTo,
    SandBoxMode,
)


def send_email(
    to_emails,
    from_email,
    subject,
    html_content,
    sandbox_mode=True,
    cc_emails=None,
    bcc_emails=None,
    reply_to=None,
):
    """
    before using, configure environment variables
    SENDGRID_MAIL_FROM={your-mail-from}
    SENDGRID_API_KEY={your-sendgrid-api-key}.
    """
    mail = Mail()
    mail.from_email = Email(from_email)
    if reply_to:
        mail.reply_to = ReplyTo(*reply_to)
    mail.subject = subject
    mail.mail_settings = MailSettings()

    if sandbox_mode:
        print("SANDBOX MODE")
        mail.mail_settings.sandbox_mode = SandBoxMode(enable=True)

    personalization = Personalization()
    for to_address in to_emails:
        personalization.add_to(Email(to_address))
    if cc_emails:
        for cc_address in cc_emails:
            personalization.add_cc(Email(cc_address))
    if bcc_emails:
        for bcc_address in bcc_emails:
            personalization.add_bcc(Email(bcc_address))
    mail.add_personalization(personalization)
    mail.add_content(Content("text/html", html_content))

    _post_sendgrid_mail(mail.get())


def _post_sendgrid_mail(mail_data):
    sg = sendgrid.SendGridAPIClient(api_key=os.getenv("SENDGRID_API_KEY"))
    response = sg.client.mail.send.post(request_body=mail_data)
    if response.status_code >= 200 and response.status_code < 300:
        print(
            "Email with subject {subject} was successfully sent to recipients: {personalizations}".format(
                **mail_data
            )
        )
    else:
        print(
            f"Failed to send out email with subject {mail_data['subject']}, status code: {response.status_code}"
        )