partner-contact/partner_email_check/readme/CONFIGURE.rst

Install python package email-validator: ``sudo pip install email-validator``.

To not allow multiple partners to have the same email address, use the
"Filter duplicate email addresses"/``partner_email_check_filter_duplicates``
setting.

To validate that email addresses are deliverable (that the hostname exists),
use the "Check deliverability of email addresses"/``partner_email_check_check_deliverability``
setting.