def key_to_sym(key)
      case key
      when Column
        key.key
      when String
        key.to_sym
      else
        key
      end
    end
def key_to_sym(key)
      case key
      when Column
        key.key
      when String
        key.to_sym
      else
        key
      end
    end
Return Symbol for +key+. Translate Column and String. Return +key+ unmodified for anything else.