如何捕获botocore的NoSuchKey异常？

我正在尝试编写“好”的python并捕获一个S3，但没有这样的关键错误：

session = botocore.session.get_session()
client = session.create_client('s3')
try:
    client.get_object(Bucket=BUCKET, Key=FILE)
except NoSuchKey as e:
    print >> sys.stderr, "no such key in bucket"

但是NoSuchKey尚未定义，我无法将其跟踪到需要定义的导入。

e.__class__是botocore.errorfactory.NoSuchKey但from botocore.errorfactory import NoSuchKey给出了一个错误，并且from botocore.errorfactory import *也不起作用，我也不想捕获一个通用错误。

from botocore.exceptions import ClientError

try:
    response = self.client.get_object(Bucket=bucket, Key=key)
    return json.loads(response["Body"].read())
except ClientError as ex:
    if ex.response['Error']['Code'] == 'NoSuchKey':
        logger.info('No object found - returning empty')
        return dict()
    else:
        raise

使用botocore 1.5，客户端句柄似乎公开了异常类：

session = botocore.session.get_session()
client = session.create_client('s3')
try:
    client.get_object(Bucket=BUCKET, Key=FILE)
except client.exceptions.NoSuchKey as e:
    print >> sys.stderr, "no such key in bucket"

在boto3中，我能够在资源的元客户端中访问异常。

import boto3

s3 = boto3.resource('s3')
s3_object = s3.Object(bucket_name, key)

try:
    content = s3_object.get()['Body'].read().decode('utf-8')
except s3.meta.client.exceptions.NoSuchKey:
    print("no such key in bucket")

我认为最完美的方式是在Boto3中

session = botocore.session.get_session()
client = session.create_client('s3')

try:
    client.get_object(Bucket=BUCKET, Key=FILE)
except client.exceptions.NoSuchKey:
    print("no such key in bucket")

有关错误处理的文档似乎很少，但是以下内容打印了适用的错误代码：

session = botocore.session.get_session()
client = session.create_client('s3')
try:
    try:
        client.get_object(Bucket=BUCKET, Key=FILE)
    except client.exceptions.InvalidBucketName:
        print("no such key in bucket")
except AttributeError as err:
    print(err)

<位于0x105e08c50的botocore.errorfactory.S3Exceptions对象>对象没有属性'InvalidBucketName'。有效的例外是：BucketAlreadyExists，BucketAlreadyOwnedByYou，NoSuchBucket，NoSuchKey，NoSuchUpload，ObjectAlreadyInActiveTierError，ObjectNotInActiveTierError