def pop_string(count = 1)
      s = stack.pop(count).map do |s|
        case s
        when Numeric
          Script.encode_number(s)
        else
          s
        end
      end
      count == 1 ? s.first : s
    end
def pop_string(count = 1)
      s = stack.pop(count).map do |s|
        case s
        when Numeric
          Script.encode_number(s)
        else
          s
        end
      end
      count == 1 ? s.first : s
    end
pop the item with the string(hex) value for the number specified by +count+ from the stack.