title: Getting following error on serverless.yaml :can not read a block mapping entry; a multiline key may not be an implicit key
body: <p>I am trying to deploy the lambda function along with the <code>serverless.yml</code> file to AWS, but it throw below error</p>
  
  <p>The following is the function defined in the YAML file</p>
  
  <pre><code>functions:
   s3-thumbnail-generator:
   handler:handler.s3_thumbnail_generator  
     events:
       - s3:
         bucket: ${self:custom.bucket}
         event: s3.ObjectCreated:*
         rules:
         - suffix: .png
  
  plugins:
    - serverless-python-requirements  
  </code></pre>
  
  <p>Error I am getting:</p>
  
  <blockquote>
    <p>can not read a block mapping entry; a multiline key may not be an implicit key in serverless.yml" at line 45, column 10:</p>
  </blockquote>
  
  <p>I would need to understand how to fix this issue in YAML file in order to deploy to the function to AWS?</p>