Global name not defined error

[Srijita173]

Using TensorFlow backend.
Epochs 200
Bathc_size 12
Batches per epoch 31
Traceback (most recent call last):
File "new_pix2pix.py", line 252, in
train(200,12)
File "new_pix2pix.py", line 209, in train
discriminator = discriminator_model()
File "new_pix2pix.py", line 147, in discriminator_model
inputs = Input(shape=(img_cols,img_rows,IN_CH*2))
NameError: global name 'img_cols' is not defined

I am getting the above error ...
Can you please help resolve this issue.