Error while Executing learn.fit function

Hello Team,

I am new to Deep Learning and not sure if this is the group which I should post. I am trying to run a simple Neural Network which is taught as part of Lesson 4 - Deep Learning for Coders (2020) .Below is my code. I am getting following error. Please help.

Code:
simple_net = nn.Sequential
(
nn.Linear(28*28,30),
nn.ReLU(),#this is a class rather than a function,
nn.Linear(30,1)
)
learn = Learner(dls,simple_net,opt_func = SGD , loss_func = mnist_loss , metrics = batch_accuracy)
learn.fit(40,0.1)
while I am executing learn.fit I am getting error:

Error
/usr/local/lib/python3.7/dist-packages/fastai/torch_core.py in trainable_params(m) 599 def trainable_params(m): 600 "Return all trainable parameters of m" --> 601 return [p for p in m.parameters() if p.requires_grad] 602 603 # Cell

TypeError: parameters() missing 1 required positional argument: ‘self’