I am working on a powerBi report and I pulled data from Azure cost management. I tried loading the usage details data into powerquery and I got this.

Expression.Error: We cannot convert the value null to type Record.
Details:
Value=
Type=[Type]

I have tried modifying the M query from the advanced editor but I am not getting it right.

This is the M query code

let
    source = AzureCostManagement.Tables("Enrollment Number", "10xxxxx", 12, [startDate=null, endDate=null]),
    usagedetails = Source{[Key="usagedetails"]}[Data]
in
    usagedetails

Kindly assist please