AttributeError: module 'google.longrunning.operations_pb2' has no attribute 'OperationsStub'というエラー

Question

前提・実現したいこと

現在、googlespeech-to-textを用いて音声ファイルをテキスト化しcsvファイルに特徴量を書き出そうと試みていますが以下のエラーが出現しています。わかる方教えていただきたいです。

発生している問題・エラーメッセージ

Traceback (most recent call last):
  File "LongRunning.py", line 137, in <module>
    transcribe_gcs(args.path)
  File "LongRunning.py", line 83, in transcribe_gcs
    operation = client.long_running_recognize(config=config, audio=audio)
  File "/home/pi/.local/lib/python3.7/site-packages/google/cloud/speech_v1/services/speech/client.py", line 508, in long_running_recognize
    self._transport.operations_client,
  File "/home/pi/.local/lib/python3.7/site-packages/google/cloud/speech_v1/services/speech/transports/grpc.py", line 236, in operations_client
    self._operations_client = operations_v1.OperationsClient(self.grpc_channel)
  File "/home/pi/.local/lib/python3.7/site-packages/google/api_core/operations_v1/operations_client.py", line 59, in __init__
    self.operations_stub = operations_pb2.OperationsStub(channel)
AttributeError: module 'google.longrunning.operations_pb2' has no attribute 'OperationsStub'

該当のソースコード

import argparse
import io
import csv
import sys
import datetime

strnow = str(datetime.datetime.now().strftime('%Y%m%d%H%M%S'))
CSVFileName ='_CSVFileLanuage' + strnow + '.csv'



def transcribe_gcs(gcs_uri):
    """Asynchronously transcribes the audio file specified by the gcs_uri."""
    from google.cloud import speech

    client = speech.SpeechClient()

    audio = speech.RecognitionAudio(uri=gcs_uri)
    config = speech.RecognitionConfig(
        encoding=speech.RecognitionConfig.AudioEncoding.FLAC,
        sample_rate_hertz=16000,
        language_code="ja-JP",
        enable_word_time_offsets=True,        
    )

    operation = client.long_running_recognize(config=config, audio=audio)

    print("Waiting for operation to complete...")
    response = operation.result(timeout=10000)


        sentence_end=0
        data=[]
        alternative = result.alternatives[0]
        print("Transcript: {}".format(alternative.transcript))
        print("Confidence: {}".format(alternative.confidence))


        for word_info in alternative.words:
            word=word_info.word
            start_time = word_info.start_time
            end_time = word_info.end_time
            if sentence_end==0:
                sentence_end=end_time.total_seconds()
            print(
                f"Word: {word}, start_time: {start_time.total_seconds()}, end_time: {end_time.total_seconds()}"
            )

        
        len_s=end_time.total_seconds()-sentence_end
        data.append(ip)
        data.append(end_time.total_seconds())
        data.append(len_s)
        data.append(alternative.transcript)

        with open(CSVFileName,'a') as csvfile:
            writer =csv.writer(csvfile, lineterminator='\n')
            writer.writerow(data)

if __name__ == "__main__":
    CSVFileName ='_CSVFileLanuage' + strnow + '.csv'

    parser = argparse.ArgumentParser(
        description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter
    )
    parser.add_argument("path", help="File or GCS path for audio file to be recognized")
    args = parser.parse_args()
    if args.path.startswith("gs://"):
        transcribe_gcs(args.path)