How to use Boolean variable as the if conditon in Python

I feel confused about the code as follows:

def findMin(alist):
    overallmin=alist[0] #define this findmin function to find the smallest 
                         number in alist,O(n^2)#
    for i in alist:
        issmallest= True
        for J in alist:
            if i>j:
               issmallest= False
        if  issmallest:
            overallmin = i
     return overallmin

I can't understand: 1,why the author set "issmallest = True" in the first for loop, at the same time, I don't know why or how to use the boolearn value as the for or while loop condition directly. Another confusion is like " while True:" this kind of situation. why they want to set the boolean here as the condition?