ArgumentError: List of aggregates should not be empty

[ShubhankarKG]

I was following the tutorial for Cubes. After creating the browser, the next command is

result = browser.aggregate()

On trying this, I got an error:

/usr/local/lib/python3.7/dist-packages/cubes/sql/browser.py in aggregation_statement(self, cell, aggregates, drilldown, split, for_summary)
    530 
    531         if not aggregates:
--> 532             raise ArgumentError("List of aggregates should not be empty")
    533 
    534         if not isinstance(drilldown, Drilldown):

ArgumentError: List of aggregates should not be empty