PCC heavily relies on the pacing mechanism.
Until recently, this mechanism did not exist in the Linux kernel.
2014 - Implementation of PCC using UDT by Mo Dong - https://github.com/modong/pcc
2016 - Google publishes their BBR congestion algorithm (CA) - an algorithm with similar goals to PCC but slightly different, as a Linux kernel module.
2016 - Google adds pacing mechanism to the Linux kernel in order to support their BBR CA approach.
2017 - Google's BRR team adds more changes - allowing internal timers to implement pacing and multiple bug fixes.
2018 - PCC Vivace released with userspace implementation over UDT - https://github.com/PCCproject/PCC-Uspace

This module was tested and developed on kernel version 4.15

Install git and clone this repository.

cd src
make
sudo insmod tcp_pcc.ko

import socket

TCP_CONGESTION = getattr(socket, 'TCP_CONGESTION', 13)

s = socket.socket()
s.setsockopt(socket.IPPROTO_TCP, TCP_CONGESTION, 'pcc')

# Use s

All PCC code resides under src/tcp_pcc.c