How to sort a nested Python dictionary?

If you have a dictionary of the following format:

{
   'KEY1':{'name':'foo','data':1351,'completed':100},
   'KEY2':{'name':'bar','data':1541,'completed':12},
   'KEY3':{'name':'baz','data':58413,'completed':18}
}

And you want to sort by the key, completed within each entry, in a ascending order, you can use the sorted function with a lambda that specifies which key to use to sort the data. For example,

my_collection = {
   'KEY1':{'name':'foo','data':1351,'completed':100},
   'KEY2':{'name':'bar','data':1541,'completed':12},
   'KEY3':{'name':'baz','data':58413,'completed':18}
}
sorted_keys = sorted(my_collection, key=lambda x: (my_collection[x]['completed']))
print(sorted_keys)

This will give the output:

['KEY2', 'KEY3', 'KEY1']