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: spec_helper.rb
    path of file: ./repos/unread/spec
    
    the code of the file until where you have to start completion: require 'simplecov'
require 'cove
    
def clear_db
  Reader.delete_all
  DifferentReader.delete_all
  StiReader.delete_all
  Email.delete_all
  ReadMark.delete_all
end