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

##
# BasicSpecification is an abstract class which implements some common code
# used by both 
    
  def contains_requirable_file?(file)
    if @ignored
      return false
    elsif missing_extensions?
      @ignored = true

      if platform == Gem::Platform::RUBY || Gem::Platform.local === platform
        warn "Ignoring #{full_name} because its extensions are not built. " \
             "Try: gem pristine #{name} --version #{version}"
      end