# File lib/premailer/premailer.rb, line 489
  def self.local_data?(data)
    return true   if data.is_a?(IO) || data.is_a?(StringIO)
    return true   if data =~ /\Afile:\/\//i
    return false  if data =~ /\A(?:(https?|ftp):)\/\//i
    true
  end