What is function of def() in python

Answer 1

There is no def() in python i think.
There is def keyword in python and
def followed by identifier with( <arguments> ) :
<function body>
will tells the interpreter the this is a function definition

ex: a function add for adding two numbers and returns sum, is :

def add( a, b ) :
sum_ab = a + b
return sum_ab;

You can use or call it as
print( add(4, 5))

or

Add = add(4, 5)
print( Add)

Answer 2

Thanx