To add the kernel implementation to GPy, follow these steps:
1. Copy the file to the GPy/kern/parts folder and compile

2. Add the following lines to GPy/kern/constructors.py
def periodic_spikes(input_dim,shape=1,period=168):
part=parts.periodic_spikes.PeriodicSpikes(input_dim,shape,period)
    return kern(input_dim,[part])

3. Add the following line to GPy/kern/parts/__init__.py
import periodic_spikes

To define the kernel:
k = GPy.kern.periodic_spikes(input_dim=1, shape=10, period=168)