Here's the completed code:
```
my_menu = {
"samosas": {"price": 5, "temperature": "hot"},
"naan": {"price": 3, "temperature": "warm"},
"chicken tikka masala": {"price": 12, "temperature": "hot"}
}
# Iterate the elements of the menu
for dish, values in my_menu.items():
# Print whether the dish must be served cold or hot
print(f"{dish.title()} is best served {values['temperature']}.")
```
The `items()` method is used to iterate over the key-value pairs in the `my_menu` dictionary. The `dish` variable represents the name of the menu item, and the `values` variable represents its price and temperature. The f-string in the `print()` statement correctly formats the output to display whether each dish is best served hot or warm.