we can also see what happens if you try to look up something that doesn' exist wellwe can use the hfu function on dictionary to safely return an entry so in this case&oufsqsjtf does have an entry in my dictionaryit just gives me back ,jslbut if call the / ship on the dictionaryi never defined the captain of thatso it comes back with /pof value in this examplewhich is better than throwing an exceptionbut you do need to be aware that this is possibilityqsjou dbqubjothfu / the output of the above code is as follows/pof the captain is jonathan archerbut you knowi' get little bit too geeky here now iterating through entries gpstijqjodbqubjot qsjou tijq dbqubjot the output of the above code is as followslet' look at little example of iterating through the entries in dictionary if want to iterate through every ship that have in my dictionary and print out dbqubjoti can type for tijq in dbqubjotand this will iterate through every single key in my dictionary then can print out the lookup value of each ship' captainand that' the output that get there there you have it this is basically the main data structures that you'll encounter in python there are some otherssuch as setsbut we'll not really use them in this bookso think that' enough to get you started let' dive into some more python nuances in our next section