def METHOD_NAME(self, sent_message, pdf_bytes):
    att = FoiAttachment(
        belongs_to=sent_message,
        name="{}_{}.pdf".format(slugify(sent_message.subject)[:25], _("redacted")),
        is_redacted=True,
        filetype="application/pdf",
        approved=True,
        can_approve=True,
    )
    pdf_file = ContentFile(pdf_bytes)
    att.size = pdf_file.size
    att.file.save(att.name, pdf_file)
    att.approve_and_save()
    return att