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# Why does the "sum" have no definition? Is it built in code?

Is "sum" only used for format statements or can they be used in other statements as well?

Hi Luke

You are correct - sum() is indeed a built-in function. Here's a list of Python's built-in functions: https://docs.python.org/3/library/functions.html

You can use sum() however you need. Here's a few examples for you:

```# Example 1

lst = [2, 4, 5, 7, 9]
print(sum(lst))     # 27 (2+4+5+7+9)

# Example 2

lst = [1, 3, 2]
print(sum(lst, 10)) # 16 (1+3+2+10)
```

Hope this helps!

Thanks! Ave!