title: "errorMessage": "Handler 'lambda_handler' missing on module 'lambda_function'",
body: <p>I was creating a bucket with below code. Is it compulsory to write lambda_function(event,context) while doing anything?</p>
  <p>Code is below</p>
  <pre><code>import json
  import boto3
  
  BUCKET_NAME = 'ly_2020_s3'
  def s3_client():
      s3 = boto3.client('s3')
      return s3
  
  def create_bucket(bucket_name):
      return s3_client().create_bucket(
          Bucket=bucket_name,CreateBucketConfiguration={'LocationConstraint':'eu-central-1'})
  
  if __name__=='__main__':
      create_bucket(BUCKET_NAME)
  </code></pre>