input: Write a function to calculate the average of the elements in a 2-dimensional array. Return the average value rounded to two decimal places. If the input array is empty, return 0.00.
  def averageMatrix(matrix):
      if not matrix:
          return 0.00
      sum = 0
      count = 0
      for row in matrix:
          for e in row:
              sum += e
              count += 1
      return round(sum / count, 2)
  
  a = [[3,2,6],
       [8,5,9],
       [4,7,1]]
  
  print(averageMatrix(a)) # 4.77
  assert averageMatrix([[3, 2, 6], [8, 5, 9], [4, 7, 1]]) == 4.77
  assert averageMatrix([[1, 2], [3, 4]]) == 2.50
  assert averageMatrix([]) == 0.00
  assert averageMatrix([[5]]) == 5.00
output: def averageMatrix(matrix):
      if not matrix:
          return 0.00
      sum = 0
      count = 0
      for row in matrix:
          for e in row:
              sum += e
              count += 1
      return round(sum / count, 2)