I would like to see your code. Its probably a mistyped word. But in the mean time please cross-check your code with mine.
I hope you are not using PyQt6, which is not ready yet. But will be ready ( I hope in version 6.1 , not 6.0.1)
But PyQt5.15 is a precursor to PyQt6
If you are using PyQt5.15, then its just a mistype word.