Hi, I do not know why besides my square function returns the variable squared, in the result windows I get None

I think it should return the value of the variable

```
def square(n):
"""Returns the square of a number."""
squared = n**2
print "%d squared is %d." % (n, squared)
return squared
# Call the square function on line 9! Make sure to
# include the number 10 between the parentheses.
square(10)
```