input: from typing import Dict
  
  class StoreItem:
      def __init__(self, item_id: int, name: str, price: float, description: str):
          """ Initialize an online store item with fields for ID, name, price, and description. """
          self.item_id = item_id
          self.name = name
          self.price = price
          self.description = description
  
      def __str__(self) -> str:
          """ Return a string representation of the store item. """
          return f'{self.name}, ${self.price}'
  
      def to_dict(self) -> Dict[str, str]:
          """ Convert the store item to a dictionary format. """
          return {
              'item_id': self.item_id,
              'name': self.name,
              'price': self.price,
              'description': self.description
          }
  
  # Example usage:
  # >>> item = StoreItem(1, 'Laptop', 899.99, 'High-performance laptop')
  # >>> print(item)
  # Laptop, $899.99
  # >>> item.to_dict()
  # {'item_id': 1, 'name': 'Laptop', 'price': 899.99, 'description': 'High-performance laptop'}
output:     
      def from_dict(cls, item_dict: Dict[str, str]) -> 'StoreItem':
          """ Create a StoreItem instance from a dictionary. """
          return cls(
              item_id=item_dict['item_id'],
              name=item_dict['name'],
              price=item_dict['price'],
              description=item_dict['description']
          )
  