def get_matching_indices pattern
      matches = []
      @obj.content.each_with_index { |e,i| 
        # convert to string for tables
        e = e.to_s unless e.is_a? String
        if e  =~ /#{pattern}/
          matches << i
        end
      }
      return matches
    end
def get_matching_indices pattern
      matches = []
      @obj.content.each_with_index { |e,i| 
        # convert to string for tables
        e = e.to_s unless e.is_a? String
        if e  =~ /#{pattern}/
          matches << i
        end
      }
      return matches
    end
returns a list of matching indices using a simple regex match on given pattern
 returns an empty list if no match