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: pipeline.rb
    path of file: ./repos/mongoid/lib/mongoid/criteria/queryable
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
# r
    
        def unwind(field_or_doc)
          unless field_or_doc.respond_to? :keys
            normalized = field_or_doc.to_s
            name = aliases[normalized] || normalized
            push("$unwind" => name.__mongo_expression__)
          else
            push("$unwind" => field_or_doc)
          end