friend CpuAction* CpuL07::sleep(double duration);
friend CpuAction* HostL07Model::execute_parallel(const std::vector<s4u::Host*>& host_list, const double* flops_amount,
const double* bytes_amount, double rate);
friend CpuAction* CpuL07::sleep(double duration);
friend CpuAction* HostL07Model::execute_parallel(const std::vector<s4u::Host*>& host_list, const double* flops_amount,
const double* bytes_amount, double rate);