alert:testEC1 - This tests the extra-credit portion
insert:H1:BWI:88
insert:H1:LAX:61
insert:H1:IAD:47
list:H1
insert:H2:SEA:96
insert:H2:CLT:82
insert:H2:BOS:72
list:H2
insert:H3:DCA:33
insert:H3:JFK:26
insert:H3:ATL:52
list:H3
insert:H4:PVD:13
insert:H4:ORD:37
insert:H4:DFW:55
list:H4
insert:H5:DEN:23
insert:H5:MIA:11
list:H5
extract:H5
update-key:H5:MIA:91
merge:H4:H5
list:H4
size:H4
list:H5
size:H5
alert:We're expecting an "Invalid locator" exception
update-key:H5:MIA:19
list:H4
alert:We're expecting an "Invalid locator" exception
update-key:H2:PVD:31
merge:H4:H5
merge:H3:H4
alert:We're expecting an "Invalid locator" exception
update-key:H5:MIA:97
alert:We're expecting an "Invalid locator" exception
update-key:H4:MIA:10
update-key:H3:MIA:99
list:H3
merge:H1:H2
list:H1
merge:H1:H3
list:H1
update-key:H1:BWI:12
list:H1
alert:We're expecting an "Invalid locator" exception 
alert:If you see "Attempt to access nonexistent locator" below, update your skeleton code
update-key:H5:DEN:93
