input: def rounded_average_in_binary(n, m):
      """You are given two positive integers n and m, and your task is to calculate the
      arithmetic mean of the numbers from n to m (n and m inclusive). 
      Round the outcome to the nearest whole number and then convert that result to a binary string.
      If n is greater than m, return -1.
      Example:
      rounded_average_in_binary(1, 5) => "0b11"
      rounded_average_in_binary(7, 5) => -1
      rounded_average_in_binary(10, 20) => "0b1111"
      rounded_average_in_binary(20, 33) => "0b11010"
      """
output:     if n > m:
          return -1
          
      count = m - n + 1
      total_sum = sum(range(n, m + 1))
      average = round(total_sum / count)
      
      return bin(average)