Fix return value if no extractor given
Fix return value if no extractor given

webmozart/assetic,renaatdemuynck/assetic,renaatdemuynck/assetic,fredemmott/assetic,lenar/assetic,mubassirhayat/assetic,lenar/assetic,lellimecnar/assetic,sportradar/assetic,shandy05/assetic,kriswallsmith/assetic,shandy05/assetic,sportradar/assetic,matthiasmullie/assetic,shandy05/assetic,Sgoettschkes/assetic,Sgoettschkes/assetic,renaatdemuynck/assetic,lellimecnar/assetic,shandy05/assetic,mubassirhayat/assetic,lenar/assetic,Sgoettschkes/assetic,webmozart/assetic,matthiasmullie/assetic,lenar/assetic,Sgoettschkes/assetic,matthiasmullie/assetic,renaatdemuynck/assetic,sportradar/assetic,fredemmott/assetic,lellimecnar/assetic,mubassirhayat/assetic,webmozart/assetic,lellimecnar/assetic,kriswallsmith/assetic,matthiasmullie/assetic,kriswallsmith/assetic,kriswallsmith/assetic,fredemmott/assetic