Add file for GPS 2.2
user
```ruby
# Method to create a list
# input: string of items separated by spaces (example: "carrots apples cereal pizza")
# steps:
  # [fill in any steps here]
  # set default quantity
  # print the list to the console [can you use one of your other methods here?]
# output: [what data type goes here, array or hash?]

# Method to add an item to a list
# input: item name and optional quantity
# steps:
# output:

# Method to remove an item from the list
# input:
# steps:
# output:

# Method to update the quantity of an item
# input:
# steps:
# output:

# Method to print a list and make it look pretty
# input:
# steps:
# output:```
assistant