title: ImportError: cannot import name 'pubsub_v1' from 'google.cloud' (unknown location)
body: <p>I am trying to import the pubsub_v1 in a cloud function. But when I tried to deploy it on GCP, the problem as in the title coming out. The requirements.txt file is in the same directory as the main.py file. Here is what in the requirements.txt:</p>
  
  <pre><code>google-api-core==1.3.0
  google-auth==1.5.1
  google-cloud-core==0.28.1
  google-cloud-storage==1.10.0
  google-resumable-media==0.3.1
  googleapis-common-protos==1.5.3
  google-api-python-client==1.7.4
  oauth2client==4.1.2
  google-cloud-bigquery==1.5.0
  google-cloud-logging==1.7.0
  google-cloud-pubsub==0.26.0
  proto-google-cloud-pubsub-v1==0.15.4
  gapic-google-cloud-pubsub-v1==0.15.4
  grpc-google-iam-v1==0.11.4
  </code></pre>
  
  <p>I used the following command to deploy the cloud function:</p>
  
  <pre><code>gcloud functions deploy some_function --runtime python37 --trigger-resource bucket --trigger-event google.storage.object.finalize --memory 2048 --timeout 500
  </code></pre>