This is not how you think Mojo works.
If you copy&paste python code into Mojo, you will not benefit from optimizations. You need to refactor your python code into Mojo code to gain compiler efficiency.
But if you look at the refactored code in the end, it is very ugly syntax (this is my personal opinion and might change with the evolution of Mojo)
Look at Taichi at Github. This library for Python seems not very popular and unaware. Maybe, because it is a Chinese development, but Taichi is simple and compiles directly down to kernels on CUDA, GPU, Metal, Vulkan and has batteries included. Beats the fastest Mojo implementation of the Mandelbrot set about 260 times faster.
https://github.com/taichi-dev/taichi
They use Claude 2 as AI backend with a 100K context window. In my experience Claude is better at programming than GPT-4 because it has a much younger cut-off date and because of the context window to process knowledge.
Halluzination happens with all LLM's.