belongsToMany(Plantel::class)->withPivot('plantel_id'); } public function nivelPlane() : BelongsToMany { return $this->belongsToMany(Plane::class); } public function existe($plantelId = null) { if (!$plantelId) { return false; } return $this->nivelPlantel() ->wherePivot('plantel_id', $plantelId) ->exists(); } }