human
Write me a the Python code you requested given the following:
I am working on the file "PyConFr2017.ipynb".
The first task is:
NB ça ne teste que les noms de membre, pas leur type...
Contrat implicite
Can you write Python code for it?
assistant
#Here is the Python code you requested.

class Twice(list):
    def append(self, value, times):
        for _ in range(times):
            super(Twice, self).append(value)

tw = Twice()
tw.append("ore", 2)
len(tw)

isinstance(tw, Members['append', '__len__'])

tw.append("aison")  # gentlemna contract again