sublist exercise causes "redeclared as different kind of entity" error

Using...

`
namespace sublis {
enum List_comparison {
equal,
sublist,
superlist,
unequal
};`

`List_comparison sublist(const std::vector& list_a, const std::vector& list_b);
}
`
... I get the following:
error: ‘sublist::List_comparison sublist::sublist(const std::vector&, const std::vector&)’ redeclared as different kind of entity

I recommend a different name for the sublist function.