src/Reflection/ReflectionClass.php
public function getParentClassNames() : array
    {
        return array_map(static function (self $parentClass) : string {
            return $parentClass->getName();
        }, array_slice(array_reverse($this->getInheritanceClassHierarchy()), 1));
    }
public function getParentClassNames() : array
    {
        return array_map(static function (self $parentClass) : string {
            return $parentClass->getName();
        }, array_slice(array_reverse($this->getInheritanceClassHierarchy()), 1));
    }
Gets the parent class names.

@return string[] A numerical array with parent class names as the values.