input: Write a Python class for an online store item that includes fields for ID, name, price, and description. Implement methods to return a string representation of the item and to convert the item 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, "Pen", 2.5, "A nice pen"))=="Pen, $2.5"
  assert StoreItem(2, "Notebook", 5.0, "Spiral notebook").to_dict()=={'item_id': 2, 'name': 'Notebook', 'price': 5.0, 'description': 'Spiral notebook'}
  assert StoreItem(3, "Eraser", 1.0, "A simple eraser").__str__()=="Eraser, $1.0"
  assert StoreItem(4, "Pencil", 1.5, "Automatic pencil").to_dict()['price']==1.5
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
          }
  