docs: def get_volumes(instance):
      """Returns all the volumes of an instance."""
      if instance.cloud == 'aws':
          client = boto3.client('ec2', instance.region)
          devices = client.describe_instance_attribute(
              InstanceId=instance.id, Attribute='blockDeviceMapping').get('BlockDeviceMappings', [])
          volumes = client.describe_volumes(VolumeIds=[device['Ebs']['VolumeId']
                                                       for device in devices if device.get('Ebs', {}).get('VolumeId')]).get('Volumes', [])
          return {volume['Attachments'][0]['Device']: {'size': volume['Size'], 'volume_type': volume['VolumeType']} for volume in volumes}
      if instance.cloud == 'gcp':
          credentials = GoogleCredentials.get_application_default()
          compute = discovery.build('compute', 'v1', credentials=credentials)
          volumes = {}
          for disk in compute.instances().get(instance=instance.id,
                                              zone=instance.zone,
                                              project=instance.project).execute()['disks']:
              index = disk['index']
              name = disk['deviceName'] if disk['deviceName'] not in [u'persistent-disk-0', 'boot'] else instance.id
              if 'local-ssd' in disk['deviceName']:
                  size = 375.0
              if 'local-ssd' in disk['deviceName']:
                  size = 375.0
                  disk_type = 'local-ssd'
              else:
                  disk_data = compute.disks().get(disk=name,
                                                  zone=instance.zone,
                                                  project=instance.project).execute()
                  size = float(disk_data['sizeGb'])
                  disk_type = 'pd-ssd'
              volumes[index] = {'size': size,
                                'type': disk['type'],
                                'deviceName': disk['deviceName'],
                                'interface': disk['interface'],
                                'diskType': disk_type}
          return volumes
      raise ValueError('Unknown cloud %s' % instance.cloud)