# File lib/premailer/premailer.rb, line 340
  def media_type_ok?(media_types)
    media_types = media_types.to_s
    return true if media_types.nil? or media_types.empty?
    media_types.split(/[\s]+|,/).any? { |media_type| media_type.strip =~ /screen|handheld|all/i }
  end