input: def compute_binary_average(n, m):
      """Given two positive integers n and m, calculate the average of integers from n to m
      (both inclusive). Round this average to the nearest whole number and return its binary 
      representation. If n is greater than m, return -1.
      Example:
      compute_binary_average(1, 5) => "0b11"
      compute_binary_average(7, 5) => -1
      compute_binary_average(10, 20) => "0b1111"
      compute_binary_average(20, 33) => "0b11010"
      """
output:     
      if n > m:
          return -1
      total = sum(range(n, m + 1))
      count = m - n + 1
      average = round(total / count)
      return bin(average)
  