def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def _getQUICHeader(self, count):
        if type(count) is not hex:
            try:
                count_id = chr(count)
            except:
                sys.stderr.write("Count must be int or hex.\n")
                return 1
        else:
            count_id = count

        if count > self.max_packets:
            sys.stderr.write("[-]\tCount must be maximum of 255.\n")
            return 1

        header = "\x0c"                     # Public Flags
        header += self.sequence             # Adding CID
        header += count_id                  # Packet Count
        return header