input: Write a function to calculate the average of the elements in a 2-dimensional array. The function should return the average value rounded to two decimal places. 
  
  def averageMatrix(matrix):
      sum = 0
      for row in matrix:
          for e in row:
              sum += e
      return round(sum / (len(matrix) * len(matrix[0])), 2)
  
  assert averageMatrix([[3,2,6], [8,5,9], [4,7,1]]) == 4.77
  assert averageMatrix([[1,2], [3,4]]) == 2.5
  assert averageMatrix([[10,20], [30,40]]) == 25.0
  assert averageMatrix([[0,0], [0,0]]) == 0.0
  assert averageMatrix([[5,15], [10,20]]) == 12.5
output: def averageMatrix(matrix):
      sum = 0
      for row in matrix:
          for e in row:
              sum += e
      return round(sum / (len(matrix) * len(matrix[0])), 2)