docs: def text_to_speech(self, text, file, voice_name=None, language=None):
          """
          Saves given text synthesized audio file, via 'CreateSpeech' endpoint
  
          Docs:
              http://developer.ivona.com/en/speechcloud/actions.html#CreateSpeech
  
          :param text: text to synthesize
          :type text: str
          :param file: file that will be used to save the audio
          :type file: file
          :param voice_name: voice name
          :type voice_name: str
          :param language: voice language
          :type language: str
          """
          endpoint = 'CreateSpeech'
  
          data = {
              'Input': {
                  'Data': text,
              },
              'OutputFormat': {
                  'Codec': self.codec.upper(),
              },
              'Parameters': {
                  'Rate': self.rate,
                  'Volume': self.volume,
                  'SentenceBreak': self.sentence_break,
                  'ParagraphBreak': self.paragraph_break,
              },
              'Voice': {
                  'Name': voice_name or self.voice_name,
                  'Language': language or self.language,
              },
          }
  
          response = self._get_response('post', endpoint, data)
  
          file.write(response.content)