public function buildNotCondition($operator, $operands)
{
if (count($operands) !== 2) {
throw new InvalidParamException("Operator '{$operator}' requires two operands.");
}
list($name, $value) = $operands;
$result = [];
if (is_array($value)) {
$result[$name] = ['$not' => $this->buildCondition($value)];
} else {
if ($name == '_id') {
$value = $this->ensureMongoId($value);
}
$result[$name] = ['$ne' => $value];
}
return $result;
}