See this sample interface with some method signatures
void CalculateSalary(string environment, string emloyeeName, ...) void GetListOfSubEmployees(string environment, string emloyeeName, ...) void CalculateBonusPerYear(string environment, string emloyeeName, ...) void GetOrderRegion(string environment, string emloyeeName, ...) void UpdateEmployee(string environment, string emloyeeName, ...) void MergePolicy(string emloyeeName, string environment, ...)
As you can see all methods have some common parameters (string environment, string emloyeeName).