[
  {
    "type": "filter",
    "column": "product",
    "operator": "eq",
    "value": "Widget"
  },
  {
    "type": "rename_column",
    "old_name": "revenue",
    "new_name": "total_sales"
  },
  {
    "type": "aggregate",
    "group_by": "region",
    "column": "total_sales",
    "function": "sum"
  }
]
