Should I fix Xcode 5 'Semantic issue: undeclared selector'?

Should I fix Xcode 5 'Semantic issue: undeclared selector'?

I'm trying to upgrade my app with Xcode5 but encountered a number of
'Semantic issues' in a third party library (the MagicalRecord one). The
quickest way to do 'fix' this might be using the:
#pragma GCC diagnostic ignored "-Wundeclared-selector"
(from: How to get rid of the 'undeclared selector' warning)
compiler directive, but my gut-feeling says this is not the appropriate
way to do this. A small code sample with the above error:
+ (NSEntityDescription *)
MR_entityDescriptionInContext:(NSManagedObjectContext *)context {
if ([self respondsToSelector:@selector(entityInManagedObjectContext:)])
{
NSEntityDescription *entity = [self
performSelector:@selector(entityInManagedObjectContext:)
withObject:context];
return entity;
}
else
{
NSString *entityName = [self MR_entityName];
return [NSEntityDescription entityForName:entityName
inManagedObjectContext:context];
}
}
where the entityInManagedObjectContext: method is not defined anywhere.
Any suggestions on how to best fix these types of errors, thanks in advance?!