code: def stats(self, variables=None, alpha=0.05, start=0,
                batches=100, chain=None, quantiles=(2.5, 25, 50, 75, 97.5)):
          
  
          # If no names provided, run them all
          if variables is None:
              variables = self._variables_to_tally
          else:
              variables = [v for v in self.variables if v.__name__ in variables]
  
          stat_dict = {}
  
          # Loop over nodes
          for variable in variables:
              # Plot object
              stat_dict[variable.__name__] = self.trace(
                  variable.__name__).stats(alpha=alpha, start=start,
                                           batches=batches, chain=chain, quantiles=quantiles)
  
          return stat_dict
docs: Statistical output for variables.
  
          :Parameters:
          variables : iterable
            List or array of variables for which statistics are to be
            generated. If it is not specified, all the tallied variables
            are summarized.
  
          alpha : float
            The alpha level for generating posterior intervals. Defaults to
            0.05.
  
          start : int
            The starting index from which to summarize (each) chain. Defaults
            to zero.
  
          batches : int
            Batch size for calculating standard deviation for non-independent
            samples. Defaults to 100.
  
          chain : int
            The index for which chain to summarize. Defaults to None (all
            chains).