How to add values to existing dictionary key Python

How to add values to existing dictionary key Python

I am trying to create a function that takes in four parameters: A keyname,
start time, end time, and then a dictionary. I have to create a tuple out
of the start time and end time and then append that to a list of tuples,
as we will be running this function multiple times. Then I am trying to
put certain parts of the list of tuples to certain keynames.
I think it's better if I would show you would the output looks like:
courses = insertIntoDataStruct("CS 2316", "1505", "1555", courses)
courses = insertIntoDataStruct("CS 2316", "1405", "1455", courses)
courses = insertIntoDataStruct("CS 2316", "1305", "1355", courses)
courses = insertIntoDataStruct("CS 4400", "1405", "1455", courses)
courses = insertIntoDataStruct("CS 4400", "1605", "1655", courses)
print(courses)
{'CS 2316': [(1505, 1555), (1405, 1455), (1305, 1355)], 'CS 4400': [(1405,
1455), (1605, 1655)]}
This is my code so far:
aDict = {}
tupleList = []
def insertIntoDataStruct(name,startTime,endTime,aDict):
timeTuple = tuple([startTime, endTime])
tupleList.append(timeTuple)
aDict[name] = tupleList
return aDict
I know that this will give me a dictionary with each key having ALL
values, but I have no idea on how to make it so that each value that I add
will be added on to the dictionary as seen in the output. I have tried a
lot of random things, but I am still stuck on this. :(