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: groups.rb
    path of file: ./repos/guard/lib/guard/internals
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require "forwardable"

require "guard/group"

module Guard
  # @private api
  module Internals
    class Groups
      extend Forwardable

      DEFAULT_GROUP = :default

    
      def matcher_for(filter)
        case filter
        when String, Symbol
          ->(group) { group.name == filter.to_sym }
        when Regexp
          ->(group) { group.name.to_s =~ filter }
        when Array, Set
          ->(group) { filter.map(&:to_sym).include?(group.name) }
        else
          fail "Invalid filter: #{filter.inspect}"
        end