RuntimeError: The graph generated form MindIR is not support to execute in the PynativeMode, please convert to the GraphMode.

import mindspore.nn as nn

net = nn.Conv2d(1,1,kernel_size=3,weight_init="ones")
input = Tensor(np.ones([1,1,3,3]).astype(np.float32))
print (input)
ms.export(net,input,file_name="net",file_foemat="MINDIR")
graph = ms.load("net.mindir")
net = nn.GraphCell(graph)
output = net(input)
print(out_put)