input: Write a function that defines a Python class for an online store item with fields for ID, name, price, and description. Additionally, provide methods to return the item as a formatted string and as a dictionary.
  assert StoreItem.__init__ !=None
  assert StoreItem.__str__ !=None
  assert StoreItem.to_dict !=None
  assert str(StoreItem('123', 'Laptop', 1000, 'High-end laptop')) == 'Laptop, $1000'
  assert StoreItem('123', 'Laptop', 1000, 'High-end laptop').to_dict() == {'item_id': '123', 'name': 'Laptop', 'price': 1000, 'description': 'High-end laptop'}
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
          }