jQuery checkbox and uniform plugin syntax

This should be a simple question for someone.  Could somebody please explain the meaning of the following two lines of code:

$("select, input[type=file]").not('select[multiple]').uniform();		
$('input:checkbox, input:radio').checkbox();

I seem to have a problem related to these lines of code, but I thought I should first understand what they are doing before I start debugging anything.

Thank you.