Mypy is not aware that changing the dtype of an array changes its annotated type, even if the dtype is passed as a literal np.dtype[np.float64], np.dtype[np.float32], etc. I imagine that this kind of ...

I look forward to your pull-request. TinyNdArray supports only float array. In the following Python code dtype=float32 is omitted, and in C++ code assuming using namespace tinyndarray; is declared.