public function getCapability($capabilityType)
{
if (!CapabilityType::isValidCapabilityType($capabilityType)) {
throw new \Exception("'" . $capabilityType . "' is not an valid capability type");
} else {
if (!isset($this->_capabilities[$capabilityType])) {
return null;
} else {
return $this->_capabilities[$capabilityType];
}
}
}