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: rollup.rb
    path of file: ./repos/manageiq/app/models/metric/ci_mixin
    
    the code of the file until where you have to start completion: module Metric::CiMixin::Rollup
  def perf_rollup_to_parents(interval_nam
    
  def perf_rollup_to_parents(interval_name, start_time, end_time = nil)
    parent_rollups, next_rollup_interval = case interval_name
                                           when 'realtime'             then [perf_rollup_parents(interval_name), 'hourly']
                                           when 'hourly', 'historical' then [perf_rollup_parents('hourly'), 'daily']
                                           when 'daily'                then [nil, nil]
                                           else raise ArgumentError, _("invalid interval name %{name}") %
                                                                       {:name => interval_name}
                                           end