Hey there!

this is the instruction:

Define a function, grades_std_deviation, that takes one argument called variance.

return the result of variance ** 0.5

Afterthe function, create a new variable called variance and store the result of calling grades_variance(grades).

Here’s relevant part of the code, which works fine:

```
def grades_std_deviation(variance):
return variance ** 0.5
variance = grades_variance(grades)
```

My question: How can python run the function (`def grades_std_deviation`

) without knowing the variable `variance`

since the variable comes **after**?

So this is a generally question about how python works.

Thanks in advance!

CR