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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_aws_credentials():
 """ Returns the values stored in the AWS credential environment variables. Returns the value stored in the AWS_ACCESS_KEY_ID environment variable and the value stored in the AWS_SECRET_ACCESS_KEY environment variable. Returns ------- out : tuple [string] The first string of the tuple is the value of the AWS_ACCESS_KEY_ID environment variable. The second string of the tuple is the value of the AWS_SECRET_ACCESS_KEY environment variable. Examples -------- ('RBZH792CTQPP7T435BGQ', '7x2hMqplWsLpU/qQCN6xAPKcmWo46TlPJXYTvKcv') """


    if (not 'AWS_ACCESS_KEY_ID' in _os.environ):
        raise KeyError('No access key found. Please set the environment variable AWS_ACCESS_KEY_ID.')
    if (not 'AWS_SECRET_ACCESS_KEY' in _os.environ):
        raise KeyError('No secret key found. Please set the environment variable AWS_SECRET_ACCESS_KEY.')
    return (_os.environ['AWS_ACCESS_KEY_ID'], _os.environ['AWS_SECRET_ACCESS_KEY'])