[BUG]Question about helpers.cpp in version core_v0.7.0

[longzhang418]

First question:
I found a bug in the helpers.cpp file about the error_argmax variable. It was declared on line 49, but the use of it on line 61 and later may trigger the error of using it without initialized.

Second question:
And when I first compiled helpers.cpp, I encountered this phenomenon. Has anyone encountered this before? Is it a problem with the pybind11/numpy.h version?

Looking forward to your reply, thank you~