Pantheon\Terminus\Models\Site::getOrganizations PHP Method

    public function getOrganizations()
    {
        $memberships = $this->getOrganizationMemberships()->all();
        $orgs = array_combine(array_map(function ($membership) {
            return $membership->organization->id;
        }, $memberships), array_map(function ($membership) {
            return $membership->organization;
        }, $memberships));
        return $orgs;
    }