'Check if this mutant is delay injectable or not.
@mutant: The mutant object that I have to inject to
:return: A vulnerability object or None if nothing is found'

def is_injectable(self, mutant):

    for delay_obj in self._get_delays():
        ed = ExactDelayController(mutant, delay_obj, self._uri_opener)
        (success, responses) = ed.delay_is_controlled()
        if success:
            desc = 'Blind    SQL    injection    using    time    delays    was    found    at:    %s'
            desc = (desc % mutant.found_at())
            response_ids = [r.id for r in responses]
            v = Vuln.from_mutant('Blind    SQL    injection    vulnerability', desc, severity.HIGH, response_ids, 'blind_sqli', mutant)
            om.out.debug(v.get_desc())
            return v
    return None
