def readShocks(self):
        '''
        Reads values of shock variables for the current period from history arrays.  For each var-
        iable X named in self.shock_vars, this attribute of self is set to self.X_hist[self.t_sim,:].

        This method is only ever called if self.read_shocks is True.  This can be achieved by using
        the method makeShockHistory() (or manually after storing a "handcrafted" shock history).

        Parameters
        ----------
        None

        Returns
        -------
        None
        '''
        for var_name in self.shock_vars:
            setattr(self,var_name,getattr(self,var_name+'_hist')[self.t_sim,:])
Reads values of shock variables for the current period from history arrays.  For each var-
        iable X named in self.shock_vars, this attribute of self is set to self.X_hist[self.t_sim,:].

        This method is only ever called if self.read_shocks is True.  This can be achieved by using
        the method makeShockHistory() (or manually after storing a "handcrafted" shock history).

        Parameters
        ----------
        None

        Returns
        -------
        None