# File lib/quickbooks/ruby_magic.rb, line 153
  def transform_keys!(trans_hash,&block)
    raise ArgumentError, "transform_keys takes a single hash argument or a block" unless trans_hash.is_a?(Hash) || block_given?
    if block_given?
      each do |k,v|
        block.call(h,k,v)
      end
    else
      trans_hash.each do |k,v|
        self[v] = self.delete(k) if self.has_key?(k)
      end
    end
    self
  end