Return an collection array of house objects whose public properties roof_color OR wall_color match the passed color para

<?php
class Subdivision {
  public $houses = []; // Same thing as array()
  public function filterHouseColor($color) {
    $lots = []; // just a temporary array 

    // Looks like this is where you got lost
    // In order to access the $houses array, you need to do $this->houses because $houses is a property on Subdivision
    // This foreach loop loops through the $houses array
    // So each cycle, $house contains a $house object found in $houses
    foreach ($this->houses as $house) {
      // Remember: you can only access $roof_color and $wall_color from the $house object
      if ($house->roof_color === $color || $house->wall_color === $color) {
        $lots[] = $house->lot; // Here, we append the value of each $house's $lot property to that temporary array up there named $lots
      }
    }

    return $lots;  // Finally, we return $lots
  }
}
?>