def critical_items(percentage = 75)
      raise ArgumentError, "Percentage must be an Integer between 0 and 100" if !percentage.between?(0, 100)
      response = api_response("critical-items", percentage)
      return response["requested_information"]
    end
def critical_items(percentage = 75)
      raise ArgumentError, "Percentage must be an Integer between 0 and 100" if !percentage.between?(0, 100)
      response = api_response("critical-items", percentage)
      return response["requested_information"]
    end
Gets the user's current items under 'Critical Items'.

 @param percentage [Integer] the maximum percentage of correctness.
 @return [Array<Hash>] critical items and their related information.