input: def elementwiseProduct(A, B):
      """Takes two matrices A and B, and produces a matrix C where each element is the product of the corresponding elements of A and B.
      >>> elementwiseProduct([[3, 4], [1, 2]], [[7, 5], [0, 1]])
      [[21, 20], [0, 2]]
      """
output:     C = []
      for i in range(len(A)):
          row = []
          for j in range(len(A[0])):
              row.append(A[i][j] * B[i][j])
          C.append(row)
      return C