code: def add_leverage(self):
                       
  
          if self.leverage is True:
              pass
          else:
              self.leverage = True
              self.z_no += 1
              self.latent_variables.z_list.pop()
              self.latent_variables.z_list.pop()
              self.latent_variables.z_list.pop()
              self.latent_variables.z_list.pop()
              self.latent_variables.add_z('Leverage Term', fam.Flat(transform=None), fam.Normal(0, 3))
              self.latent_variables.add_z('Skewness', fam.Flat(transform='exp'), fam.Normal(0, 3))
              self.latent_variables.add_z('v', fam.Flat(transform='exp'), fam.Normal(0, 3))
              self.latent_variables.add_z('Returns Constant', fam.Normal(0,3,transform=None), fam.Normal(0, 3))
              self.latent_variables.add_z('GARCH-M', fam.Normal(0,3,transform=None), fam.Normal(0, 3))
              self.latent_variables.z_list[-3].start = 2.0
docs: Adds leverage term to the model
  
          Returns
          ----------
          None (changes instance attributes)