input: from typing import List
  
  def find_min_value(int_list: IntList) -> int:
      """ Returns the minimum value stored in the IntList object.
      >>> int_list = IntList()
      >>> int_list.add_value(3)
      >>> int_list.add_value(1)
      >>> int_list.add_value(4)
      >>> find_min_value(int_list)
      1
      """
output:     if not int_list.values:
          raise ValueError("The list is empty")
      return min(int_list.values)