# File lib/qbxml/support.rb, line 124
  def transform_keys!(trans_hash)
    raise ArgumentError, "transform_keys takes a single hash argument" unless trans_hash.is_a?(Hash)
    self.each_key do |k|
      self[trans_hash.has_key?(k) ? trans_hash[k] : k] = self.delete(k)
    end
    self
  end