# It isn't working python

#1

a = 0b11101110
It is still showing this error Make sure your answer is a binary string.

#2

The point of the exercise is to flip the bits in `a`. What does that mean? Hmm, think about it. It means to turn the `1`s into `0`s and `0`s into `1`s.

You’re giving that

`a = 0b11101110` and once you apply the mask, it should flip the bits to be:

`a = 0b00010001`.

Do you see now what flipping the bits results in? If no, ask me and we’ll go further.

If yes, next you need to set the `mask` to a binary value that when you use XOR `^` it flips the bits.

What did you learn about XOR? Here’s the truth table:

So remember, for every given bit in a and b:

0 ^ 0 = 0
0 ^ 1 = 1
1 ^ 0 = 1
1 ^ 1 = 0

`0 ^ 1 = 1` So if a bit is `0` and the mask bit is `1`, then the bit flips. Right? It becomes a `1`.

`1 ^ 0 = 0` So if a bit is `1` and the mask bit is `0`, then the bit flips. Right? It becomes a `0`.

Now use that logic to layout the bits in the `mask`.

#3

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