public function testIsNANPACountry()
{
$this->assertTrue($this->phoneUtil->isNANPACountry(RegionCode::US));
$this->assertTrue($this->phoneUtil->isNANPACountry(RegionCode::BS));
$this->assertFalse($this->phoneUtil->isNANPACountry(RegionCode::DE));
$this->assertFalse($this->phoneUtil->isNANPACountry(RegionCode::ZZ));
$this->assertFalse($this->phoneUtil->isNANPACountry(RegionCode::UN001));
$this->assertFalse($this->phoneUtil->isNANPACountry(null));
}