Python recursion is a technique where a function calls itself repeatedly until a specific condition is met. This can be useful for solving problems that can be broken down into smaller, similar sub-problems. Here’s an example of a recursive function in Python:

```
def factorial(n):
if n == 0:
return 1
else:
return n * factorial(n-1)
print(factorial(5))
```

In this example, we’re defining a recursive function `factorial`

that calculates the factorial of a number. The factorial of a number is the product of all positive integers up to and including that number. For example, 5! (read “5 factorial”) is 5 x 4 x 3 x 2 x 1, which equals 120.

The `factorial`

function takes one parameter `n`

, which is the number we want to calculate the factorial of. Inside the function, we have a base case and a recursive case. The base case is when `n`

is equal to 0. In this case, we return 1, because the factorial of 0 is 1 by definition.

The recursive case is when `n`

is greater than 0. In this case, we return `n`

multiplied by the result of calling `factorial`

with `n-1`

as the argument. This means that we’re calling the `factorial`

function again with a smaller value of `n`

, and multiplying the result by `n`

. This process continues until we reach the base case (when `n`

is equal to 0), at which point the function returns 1 and the recursion stops.

When we call the `factorial`

function with `factorial(5)`

, the output will be 120, which is the factorial of 5. The function called itself five times (once for each integer from 5 down to 1) to calculate the final result.

Recursion can be a powerful technique, but it’s important to use it carefully, as it can easily lead to infinite loops if the base case is not well-defined or if the recursion depth becomes too large.