## Functions

- The first step to code reuse is the function.
- A function is a block of code that can take any number of input
*parameters*and return any number or type of output*results* - Define a function with def
- syntax:

`def <function>(<parameters>): pass`

- example:

`def add(a, b): return a + b print(add(1,2))`

- In the function return keyword returns the evaluated result to the caller and it is not necessary that every function needs to have return. The function without return value return
`None`

- Lets quickly write a program which has some functions
- Refer Here for the program which has function
`is_prime`

and its usage in the same python file (module)

- Lets try to create reusable functions for calculating
- simple interest
- compound interest
- Refer Here for the solution