public function removeStudy($formation, $forlife)
{
$formation_id = $formation instanceof Formation ? $formation->id() : $formation;
XDB::execute('DELETE FROM studies
WHERE uid = {?} AND formation_id = {?}
AND forlife = {?}', $this->id(), $formation_id, $forlife);
if (!(XDB::affectedRows() > 0)) {
return false;
}
$this->select(UserSelect::studies());
return true;
}