code: func (brng BetaGenerator) Beta(alpha, beta float64) float64 {
  	if !(alpha > 0.0) {
  		panic(fmt.Sprintf("Invalid parameter alpha: %.2f", alpha))
  	}
  	if !(beta > 0.0) {
  		panic(fmt.Sprintf("Invalid parameter beta: %.2f", beta))
  	}
  	return brng.beta(alpha, beta)
  }
docs: // Beta returns a random number of beta distribution (alpha > 0.0 and beta > 0.0)