The name of a function will generally tell a reader what the function does. Above in the header (or signature) line, the name is
cube which suggests the return value will the cube of the argument.
Your return line from that function does not seem to agree with my observation.
This is where we are supposed to call the
cube() function with
number as the argument.
The colon belongs on the
else: and a boolean is not a string. In Python it’s either
False, no quotes.