Function to reduce the scanning angle with pyhton API

[rapof]

I would like to reduce the scan angle of YDLidar X4 to 0.43 deg, currently it's 0.87 deg.
I've try to change the following setting but it do not work:

What is the function to reduce resulution?

I add another issue that mybe is connected with the first:

When I try to run the test example "./tri_test", I got the following