Regarding exercise of data structure

Hi, here is a question regarding the exercise of data structures chapter of python.
Here is the code what the course stated:

sentence = “This is a common interview question”
a = sorted(char_frequency.items(),
key=lambda kv:kv[1],
reverse=True)
print(a)
and the output of first is a touple: (‘i’,5).

But why if I divided them into as the following steps, the first output is gonna be (" ", 5), this output exist in the above code as well, just not be the first output.

sentence = “This is a common interview question”
tupledList= sorted(sentences.items())
tupledList.sort(key=lambda kv:kv[1], reverse=True)
print(tupledList)

Thank you.