    async def authenticate(self, handler, data):
        """Checks against a global password if it's been set. If not, allow any user/pass combo"""
        if self.password:
            if data['password'] == self.password:
                return data['username']
            return None
        return data['username']
Checks against a global password if it's been set. If not, allow any user/pass combo
jupyterhub/auth.py