ensure_required_ruby_version_met

# File lib/rubygems/installer.rb, line 540
  def ensure_required_ruby_version_met
    if rrv = spec.required_ruby_version then
      unless rrv.satisfied_by? Gem.ruby_version then
        raise Gem::InstallError, "#{spec.name} requires Ruby version #{rrv}."
      end
    end
  end