ITkPIxV1 register read issue

Issue as described by Lingxin Meng in mattermost:

Hi, I'm trying to test ITkPix through chip simulations and learning to develop basic scans. I want to access a chip register without looping through all of them, but by calling a specific one. As I understood the registerobject is a dictionary, i can print out self.chip.registers.keys() so in principle you could do e.g. reg = self.chip.registers['PIX_MODE'], however, this gives me the error ERROR Unknown format code 'd' for object of type 'str'