def is_safe_attribute(self, obj, attr, value):
        return not (attr.startswith('_') or is_internal_attribute(obj, attr))
The sandboxed environment will call this method to check if the
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/jinja2-2.6/jinja2/sandbox.py/SandboxedEnvironment.is_safe_attribute