Swapping the 6th bit in a Decimal Number

def bin_check(n): # n ==> Any Decimal Number
    L1 = list(bin(n))
    str1 = ''

    if L1[-6] == '0':
        L1[-6] = '1'

    for i in L1:
        str1 += i

    return str1

val = bin_check(100)
print(val)