def reverse(self):
        'S.reverse() -- reverse *IN PLACE*'
        n = len(self)
        for i in range(n//2):
            self[i], self[n-i-1] = self[n-i-1], self[i]
def reverse(self):
        'S.reverse() -- reverse *IN PLACE*'
        n = len(self)
        for i in range(n//2):
            self[i], self[n-i-1] = self[n-i-1], self[i]
def reverse ( self ) : n = len ( self ) for i in range ( n // 2 ) : self [ i ] , self [ n - i - 1 ] = self [ n - i - 1 ] , self [ i ]
S.reverse() -- reverse *IN PLACE*
S . reverse () -- reverse * IN PLACE *