input: Write a function to calculate the element-wise product of two matrices A and B, producing a new matrix C where each element in C is the product of the corresponding elements from A and B. If A and B have the same dimensions, return an error message indicating that the element-wise product is not possible.
  assert elementwise_product([[3, 4], [1, 2]], [[7, 5], [0, 1]])==[[21, 20], [0, 2]]
output: def elementwise_product(A, B):
      if len(A) != len(B) or len(A[0]) != len(B[0]):
          return "Error: The matrices must have the same dimensions for element-wise product."
      return [[A[i][j] * B[i][j] for j in range(len(A[0]))] for i in range(len(A))]