Question: I have a Django application running using Django CMS.
I am trying to make one specific submenu not clickable.

The menu is like this:

```
item1|item2|item3
            sub_item3
            sub_item3

```

What I want is that everything is clickable except for "item3" menu item.

How can I achieve this knowing item3 is a Django CMS page itself as are each of its children pages?

The idea behind this is to prevent that the user sees an empty page when he clicks on the top "item3" menuitem.

Answer: 
Multiplying by a power of two *x* is the same as left shifting by *log2(x)*:

```
  x *= 2   ->    x <<= 1
  x *= 4   ->    x <<= 2
     .
     .
     .
  x *= 32  ->    x <<= 5

```

The `&` doesn't do the shift - it just masks the bottom three bits. The syntax used in your example is a bit weird - it's using a hexadecimal character literal `'\x07'`, but that's literally identical to hex `0x07`, which in turn in binary is:

```
  00000111

```

Since any bit ANDed with `0` yields `0` and any bit ANDed with `1` is itself, the `&` operation in your example simply gives a result of being the bottom three bits of `dwWriteDataWordAddress`.
It's a bit obtuse but essentially you're anding with `0x07` and then multiplying by `32` which is the same as shifting by `5`. I'm not sure why a character literal is used rather than an integer literal but perhaps so that it is represented as a single byte rather than a word.

The equivalent would be:

```
( ( dw & 0x07 ) << 5 )

```

The `& 0x07` masks off the first 3 bits and `<< 5` does a left shift by 5 bits.