fib = {1: 1, 2: 1, 3: 2, 4: 3} print(fib.get(4, 0) + fib.get(7, 5))

Question

What is the output? it is shown the output as 8. How does it come?

Answer 1

get(4,0) tries to fetch the value associated with key 4, and if that key is not found, returns 0. In this case, there's a value for key 4, which is 3, thus 3 is returned.
Similarly, get(7,5) looks for key 7 into the dictionary. But there's no such key, and then the default value 5 is returned.
Now do the math: 3 + 5.

Answer 2

The get not explained very well...

Syntax
Following is the syntax for get() method −
dict.get(key, default=None)
Parameters
key -- This is the Key to be searched in the dictionary.
default -- This is the Value to be returned in case key does not exist.
Return Value
This method return a value for the given key. If key is not available, then returns default value None.