Updating examples

Hi, I just wanted to ask which parts of the examples "need to be updated":

```
def demo(seed=None):
    """
    Create a discrete time Hawkes model and generate from it.
    :return:
    """
raise NotImplementedError("This example needs to be updated.")
```
from 

> /examples/inference/standard_bfgs_demo.py

 and other files.

Thanks in advance.