Code improvement opportunities

[fanpu]

Expected Behavior

N/A, same behavior, syntax change

Actual Behavior

N/A, same behavior, syntax change

Steps to Reproduce the Behavior

N/A, same behavior, syntax change

From this comment #160 (comment):

Most if not all of the keys() calls in the code do not require the list form of the keys (you only need to listify the keys if you either want to use [] to access elements of the key list, or if you will alter the dict while iterating over the keys). Furthermore, a more readable way to do
if vmName in self.machines.keys():

would be to implement __contains__ in the Tango*Dictionary classes themselves and then call

if vmName in self.machines:

instead. TangoRemoteDictionary could use HEXISTS to implement __contains__ and not have to fetch everything.

[clairecw]

Fixed by #187 ?