def __repr__(self):
        return "<NamedRequirements({}{})>".format(
            self.name,
            ", filename='{}'".format(self.filename.name) if self.filename
            else "")
def __init__(self, masked_tokens=None, name='accuracy', dtype=None):
    self._masked_tokens = masked_tokens or []
    super().__init__(name, dtype=dtype)