Steven Parker182,438 Points
The instructions say that the function "takes a single argument, which will be a list ...". So when declaring the argument, you need only the name. The fact that it is a list doesn't have to be indicated in the declaration.
Also, since Python uses the word "list" internally, another name might be a better choice for the parameter.
And since the list will contain everything the function needs to work with, you won't need to "input" anything.