def index_of( item )
      max = self.get_length
      #puts "length #{max} #{max.class}"
      counter = 0
      while( counter < max )
        if( get(counter) == item)
          return counter
        end
        counter = counter + 1
      end
      return nil
    end
def index_of( item )
      max = self.get_length
      #puts "length #{max} #{max.class}"
      counter = 0
      while( counter < max )
        if( get(counter) == item)
          return counter
        end
        counter = counter + 1
      end
      return nil
    end
def index_of ( item ) max = self . get_length #puts "length #{max} #{max.class}" counter = 0 while ( counter < max ) if ( get ( counter ) == item ) return counter end counter = counter + 1 end return nil end
index of item
 return  nil if no such item
index of item return nil if no such item