About create validation set and sample for cats and dogs

I have a question about this part.
When we use below code in lesson2 to create a valid set, the number of cats and dogs images are not follow a 1:1 distribution, right? If its better to make a uniform distribution of lable for valid set?

Hi all, I am working on camera model Identification on kaggle using fastai package, the package requires that my data have a validation data saved in data, and I have tried to use the above approach to create a validation dataset, however I was getting file not found Error
Here is the image of the error
I have tried changing the paths, used the full path to valid in os.rename and also tried using shutil - move . I don’t know if there is any other approach or am I missing something.