title: Mock: Client does not have the attribute 'get_object'
body: <p>I am trying to patch the S3 <code>get_object</code> method from the boto3 module but I keep getting the following error </p>
  
  <p><code>AttributeError: &lt;function client at 0x104570200&gt; does not have the attribute 'get_object'
  </code></p>
  
  <p>This is baffling because I am able to successfully patch the <code>boto3.client</code> but not <code>boto3.client.get_object</code> , even though the boto3 documentation states that it is one of the methods for the client</p>
  
  <p>Here is my code</p>
  
  <pre><code>import boto3
  from mock import patch
  
  @pytest.mark.parametrize(
      'response, expected',
      [
          (200, True),
          (400,False)
      ]
  )
  
  @patch('boto3.client.get_object')
  def test_get_file(mock, response, expected):
      mock.return_values = response
      test = get_file('portfolio/test.xls')
      assert test == expected
  
  def get_file(self, key):
      S3 = boto3.client('s3')
      response = S3.get_object(bucket='portfolios', key=key)
      if response.status == 200:
          return response
  
      return False
  </code></pre>