code: def get_array(self, variable_name, period):
          
          if period is not None and not isinstance(period, periods.Period):
              period = periods.period(period)
          return self.get_holder(variable_name).get_array(period)
docs: Return the value of ``variable_name`` for ``period``, if this value is alreay in the cache (if it has been set as an input or previously calculated).
  
              Unlike :any:`calculate`, this method *does not* trigger calculations and *does not* use any formula.