What should be the type of the data I return through the __getitem__ method of the dataloader class if I use the default collate_fn? I am confused because the dimensions I get are different depending on the type that I return.
If I return a list, then the length of my data is 34 instead of batch_size.
def __getitem__(self, index):

    df = self.df.iloc[index]
    keypoint = df["keypoint"]
    # print(type(keypoint)) = <class 'list'>
    # print(np.shape(keypoint)) = (34,)                                                                                                                        
    return keypoint

If I return a tensor, then the length of my data is batch_size. What is happening in the collate_fn?
def __getitem__(self, index):

    df = self.df.iloc[index]
    keypoint = torch.Tensor(np.array(df["keypoint"]))                                                                                                                         
    return keypoint