expand_your_interfaces_1.go

// Provider interface for your object
type PatientProvider interface {
    PatientByID(id int) Patient
    InactivePatients() []Patient
}

// Dependency interface needed by object
type SQLExecutor interface {
    ExecuteSQL(sql string) []SQLRecord
}

// Given for completeness
type Patient struct {
    Id int
    name string
}
type SQLRecord []interface{}