Create a monthlyCostInstance. This is used by objects for storing their costs on their configs.
Create a monthlyCostInstance. This is used by objects for storing their costs on their configs.
1 number waterCost
the monthly cost of water.
2 number electricityCost
the monthly cost of electricity.
3 number communal
the monthly cost of communal services.
object-the newly-created monthlyCostInstance.