English is not my first language but it seems obvious to me that the
suggestion is using:

>>> key in dict

...instead of:

>>> dict.has_key(key)


The only thing which may be confusing is the dictionary which is first
called "dict" and then "d", in which case the following modification
should be made:

- dict.has_key(key) is equivalent to key in d, but deprecated.
+ dict.has_key(key) is equivalent to key in dict, but deprecated.