How to use the traittypes.traittypes.Array function in traittypes

if value is None and not self.allow_none:
            self.error(obj, value)
        if value is None or value is Undefined:
            return super(Array, self).validate(obj, value)
        try:
            r = np.asarray(value, dtype=self.dtype)
            if isinstance(value, np.ndarray) and r is not value:
                warnings.warn(
                    'Given trait value dtype "%s" does not match required type "%s". '
                    'A coerced copy has been created.' % (
                        np.dtype(value.dtype).name,
                        np.dtype(self.dtype).name))
            value = r
        except (ValueError, TypeError) as e:
            raise TraitError(e)
        return super(Array, self).validate(obj, value)