def loads(self, requirements_text):
        lines = re.findall(Requirement.spec_regex,
                           requirements_text,
                           re.MULTILINE)
        for line in lines:
            self.add(Requirement(line[0], "".join(line[1:])))
def _get(delta, start):
            p = start
            while delta:
                p = p.next
                delta -= 1
            return p.val