哪种 Python socket 构造方式可以选择 IPv4 TCP 端点？
socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket.import(AF_INET, SOCK_STREAM)