input: Write a function to generate a Python class for an online store item that includes fields for ID, name, price, and description. The class should have an initializer method to set the fields and a method to return the item details as a string. Additionally, include a method to convert the item details to a dictionary format.
  assert StoreItem(1, 'Book', 10.99, 'A novel by an acclaimed author').__str__() == 'Book, $10.99'
  assert StoreItem(2, 'Pen', 1.99, 'A pack of 10 high-quality pens').to_dict() == {'item_id': 2, 'name': 'Pen', 'price': 1.99, 'description': 'A pack of 10 high-quality pens'}
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:.2f}"
  
      def to_dict(self):
          return {
              'item_id': self.item_id,
              'name': self.name,
              'price': self.price,
              'description': self.description
          }