miniRT subject says to "return" a string when an error is encountered

[DutChen18]

Project Name
miniRT

What is the issue
On page 6 the subject seems to suggest that when an error is encountered when parsing the scene file the program should "return" the string "Error\n"

Expectation
Returning a string makes no sense in this context, it should instead say to print or write the string "Error\n" and possibly further specify the appropriate output stream to write the string to.

Additional context
None