With n_samples=0, test_size=0.2 and train_size=None, the resulting train set will be empty. Adjust any of the aforementioned parameters.

The error message indicates that the combination of parameters you have specified will result in an empty training set.

When you set `train_size=None`, the training set will be automatically set to the complement of the test set, which is calculated as `1 - test_size`.

If you set `n_samples=0`, this means that there are no samples available to create a training set.

To fix this error, you can adjust the values of `n_samples`, `test_size`, and `train_size` until you have a valid combination. For example, you can set a non-zero value for `n_samples`, or adjust the values of `test_size` and `train_size` to ensure that there are enough samples for both sets.