Introduction
Dictionary basics
Dictionaries in loops and conditional statements
Dictionaries in functions
13. Modifying dictionaries in functions
Summary

## Instruction

Amazing! When using dictionaries in functions, remember the following: if you modify a dictionary inside a function, this modification will be applied to your dictionary outside the function as well.

def zero_negative(dictionary_to_check):
for key in dictionary_to_check.keys():
if dictionary_to_check[key] < 0:
dictionary_to_check[key] = 0


In the function above, we modify the original dictionary, so any changes inside will affect the dictionary passed in as the argument.

## Exercise

Write a function named add_ten() that takes a dictionary whose values are numbers. The function should add 10 to every even value in the dictionary.

### Stuck? Here's a hint!

Use the following condition to check if a given dictionary value is even:

if dictionary[key] % 2 == 0: