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
async def echo_client_streams(reader, writer):
    sock = writer.get_extra_info('socket')
    try:
        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
    except (OSError, NameError):
        pass
    if PRINT:
        print('Connection from', sock.getpeername())
    while True:
        data = await reader.read(1000000)
        if not data:
            break
        writer.write(data)
    if PRINT:
        print('Connection closed')
    writer.close()