input: Write a function to calculate the average of the elements in a 2-dimensional array. If the array is empty or any of its rows are empty, return 0.
  assert averageMatrix([[3,2,6], [8,5,9], [4,7,1]])==4.77
  assert averageMatrix([[1,2], [3,4]])==2.5
  assert averageMatrix([[5,5], [5,5]])==5.0
  assert averageMatrix([[]])==0
  assert averageMatrix([])==0
output: def averageMatrix(matrix):
      if not matrix or any(not row for row in matrix):
          return 0
      total_sum = sum(sum(row) for row in matrix)
      total_elements = sum(len(row) for row in matrix)
      return round(total_sum / total_elements, 2)