You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: store.rb
    path of file: ./repos/spree/core/lib/spree/core/preferences
    
    the code of the file until where you have to start completion: # Use singleton class Spree::Preferences::Store.instance to access
#
# StoreInstance has a persistence flag that is on by default,
# but we di
    
    def get(key)
      # return the retrieved value, if it's in the cache
      # use unless nil? in case the value is actually boolean false
      #
      unless (val = @cache.read(key)).nil?
        return val
      end