@classmethod
    def registered(cls, username):
        if any(usr['username'] == username for usr in cls.getall().values()):
            return True
        return False
Yield a tuple of ``(fieldname, value)`` for each field in ``node._fields``
dataset/ETHPy150Open mekarpeles/waltz/waltz/__init__.py/User.registered--crossover with--dataset/ETHPy150Open eBay/restcommander/play-1.2.4/python/Lib/ast.py/iter_fields