input: Write a function that defines a Python class for an online store item, which includes fields for ID, name, price, and description. The class should also contain methods to convert the item to a string and to a dictionary.
  
  class StoreItem:
      def __init__(self, item_id, name, price, description):
          self.item_id = item_id
          self.name = name
          self.price = price
          self.description = description
  
      def __str__(self):
          return f'{self.name}, ${self.price}'
  
      def to_dict(self):
          return {
              'item_id': self.item_id,
              'name': self.name,
              'price': self.price,
              'description': self.description
          }
  
  assert str(StoreItem(1, "Book", 10.99, "A great read")) == "Book, $10.99"
  assert StoreItem(2, "Pen", 1.99, "Black ink pen").to_dict() == {'item_id': 2, 'name': 'Pen', 'price': 1.99, 'description': 'Black ink pen'}
  assert StoreItem(3, "Notebook", 5.49, "A5 size ruled").to_dict() == {'item_id': 3, 'name': 'Notebook', 'price': 5.49, 'description': 'A5 size ruled'}
output: class StoreItem:
      def __init__(self, item_id, name, price, description):
          self.item_id = item_id
          self.name = name
          self.price = price
          self.description = description
  
      def __str__(self):
          return f'{self.name}, ${self.price}'
  
      def to_dict(self):
          return {
              'item_id': self.item_id,
              'name': self.name,
              'price': self.price,
              'description': self.description
          }