src/Browser/Browser.php
public function sendKeys($pageId, $elementId, $keys) {
    return $this->command('send_keys', $pageId, $elementId, $this->normalizeKeys($keys));
  }
public function sendKeys($pageId, $elementId, $keys) {
    return $this->command('send_keys', $pageId, $elementId, $this->normalizeKeys($keys));
  }
TODO: not sure what this does, needs to do normalizeKeys
@param int   $pageId
@param int   $elementId
@param array $keys
@return mixed