input: Write a function called elementwiseMultiplication that takes two matrices, A and B, and returns a new matrix C where each element c_ij in C is the product of the corresponding elements a_ij in A and b_ij in B. The function should return None if the two matrices A and B are not of the same size.
  
  assert elementwiseMultiplication([[3, 4], [1, 2]], [[7, 5], [0, 1]]) == [[21, 20], [0, 2]]
  assert elementwiseMultiplication([[3, 4], [1, 2]], [[2, 3], [1, 0]]) == [[6, 12], [1, 0]]
  assert elementwiseMultiplication([[3, 4], [1, 2]], [[2, 3, 0], [1, 0, 1]]) == None
  assert elementwiseMultiplication([[1], [2]], [[3], [4]]) == [[3], [8]]
  assert elementwiseMultiplication([], []) == []
output: def elementwiseMultiplication(A, B):
      if len(A) != len(B) or any(len(rowA) != len(rowB) for rowA, rowB in zip(A, B)):
          return None
      return [[a * b for a, b in zip(rowA, rowB)] for rowA, rowB in zip(A, B)]