pkg flag, func Args() []string
pkg flag, func Bool(string, bool, string) *bool
pkg flag, func BoolVar(*bool, string, bool, string)
pkg flag, func Duration(string, time.Duration, string) *time.Duration
pkg flag, func DurationVar(*time.Duration, string, time.Duration, string)
pkg flag, func Float64(string, float64, string) *float64
pkg flag, func Float64Var(*float64, string, float64, string)
pkg flag, func Int(string, int, string) *int