private function fillKey()
    {
        $languages = $this->manager->languages();

        if ($this->languageKey) {
            if (! in_array($this->languageKey, $languages)) {
                $this->error(sprintf('Language (%s) could not be found!', $this->languageKey));

                return;
            }

            // If a language key was specified then we prompt for it only.
            $languages = [$this->languageKey];
        }

        $values = $this->collectValues($languages);

        $this->manager->fillKeys(
            str_replace($this->packageName.'::', '', $this->fileName),
            [$this->key => $values]
        );

        foreach ($values as $languageKey => $value) {
            $this->line("<fg=yellow>{$this->fileName}.{$this->key}:{$languageKey}</> was set to \"<fg=yellow>{$value}</>\" successfully.");
        }
    }