code: def _pdf_w_mean(self, x, mean, sigma):
          
  
          # Lognorm pmf with mean for optimization
          mu, sigma = self.translate_args(mean, sigma)
          return self.logpdf(x, mu, sigma)
docs: Calculates the pdf of a lognormal distribution with parameters mean
          and sigma
  
          Parameters
          ----------
          mean : float or ndarray
              Mean of the lognormal distribution
          sigma : float or ndarray
              Sigma parameter of the lognormal distribution
  
          Returns
          -------
          : float or ndarray
              pdf of x