public function caseSensitive($caseSensitive)
{
if (!isset($this->query['$text'])) {
throw new BadMethodCallException('This method requires a $text operator (call text() first)');
}
// Remove caseSensitive option to keep support for older database versions
if ($caseSensitive) {
$this->query['$text']['$caseSensitive'] = true;
} elseif (isset($this->query['$text']['$caseSensitive'])) {
unset($this->query['$text']['$caseSensitive']);
}
return $this;
}