promql/functions.go
func funcDaysInMonth(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return dateWrapper(vals, enh, func(t time.Time) float64 {
		return float64(32 - time.Date(t.Year(), t.Month(), 32, 0, 0, 0, 0, time.UTC).Day())
	})
}
func funcDaysInMonth(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return dateWrapper(vals, enh, func(t time.Time) float64 {
		return float64(32 - time.Date(t.Year(), t.Month(), 32, 0, 0, 0, 0, time.UTC).Day())
	})
}
// === days_in_month(v Vector) Scalar ===