instance method symbol_unscoping

# File activerecord/lib/active_record/relation/query_methods.rb, line 988
    def symbol_unscoping(scope)
      if !VALID_UNSCOPING_VALUES.include?(scope)
        raise ArgumentError, "Called unscope() with invalid unscoping argument ':#{scope}'. Valid arguments are :#{VALID_UNSCOPING_VALUES.to_a.join(", :")}."
      end

      clause_method = Relation::CLAUSE_METHODS.include?(scope)
      multi_val_method = Relation::MULTI_VALUE_METHODS.include?(scope)
      if clause_method
        unscope_code = "#{scope}_clause="
      else
        unscope_code = "#{scope}_value#{'s' if multi_val_method}="
      end

      case scope
      when :order
        result = []
      else
        result = [] if multi_val_method
      end

      self.send(unscope_code, result)
    end