PyQt - Question on QListWidget's selectedItems Method

[Kelie]

Another question I have about QListWidget is when user manually
selects and deselects a QListWidgetItem, the background color switches
between blue and white. But when an item is programmingly selected
with setItemSelected method, the background color is some kind of
light gray instead of blue. Why is there such a difference and how do
I programmingly set the QListWidgetItem background color to blue?

Thank you!