title: What is transformation_ctx used for in aws glue?
body: <p><a href="https://docs.aws.amazon.com/glue/latest/dg/aws-glue-api-crawler-pyspark-extensions-glue-context.html" rel="noreferrer">There are</a> a lot of methods in API which received this with default "" value.</p>
  
  <p>Is it just string marker but again what it purpose?</p>