Bug in tutorial notebook

[radka-j]

Hi!

We tried running the cross validation notebook and got the following error when running cell 12:

AttributeError: module `harmonic.model` has no attribute `KernelDensityEstimate`

[alicjapolanska]

Thank you for pointing this out @radka-j ! We fixed the import to align with the new structure, it should be all good now! 😄