'Get caption languages available for a video.
Returns:
dict: Language Codes(\'en\', \'zh\' etc) as keys and Language Names as Values(\'English\', \'Chinese\' etc)'

@property
def caption_languages(self):

    languages_selector = self.get_element_selector(CSS_CLASS_NAMES['captions_lang_list'])
    language_codes = self.q(css=languages_selector).attrs('data-lang-code')
    language_names = self.q(css=languages_selector).attrs('textContent')
    return dict(zip(language_codes, language_names))
