def get_columns
      if @column_options.has_key? :only
        return @column_options[:only] if @column_options[:only].is_a?(Array)
        [ @column_options[:only] ]
      elsif @column_options.has_key? :except
        return content_columns - @column_options[:except] if @column_options[:except].is_a?(Array)
        content_columns - [ @column_options[:except] ] 
      else
        content_columns
      end
    end
def get_columns
      if @column_options.has_key? :only
        return @column_options[:only] if @column_options[:only].is_a?(Array)
        [ @column_options[:only] ]
      elsif @column_options.has_key? :except
        return content_columns - @column_options[:except] if @column_options[:except].is_a?(Array)
        content_columns - [ @column_options[:except] ] 
      else
        content_columns
      end
    end
Return an Array of the columns based on options :only or :except