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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def verify(self) -> None: """Raises a |RuntimeError| if at least one of the required values of a |Variable| object is |None| or |numpy.nan|. The descriptor `mask` defines, which values are considered to be necessary. Example on a 0-dimensional |Variable|: Traceback (most recent call last):
 RuntimeError: For variable `var`, 1 required value has not been set yet. Example on a 2-dimensional |Variable|: Traceback (most recent call last):
 RuntimeError: For variable `var`, 2 required values \ have not been set yet. Traceback (most recent call last):
 RuntimeError: For variable `var`, 1 required value has not been set yet. """

        nmbnan: int = numpy.sum(numpy.isnan(
            numpy.array(self.value)[self.mask]))
        if nmbnan:
            if nmbnan == 1:
                text = 'value has'
            else:
                text = 'values have'
            raise RuntimeError(
                f'For variable {objecttools.devicephrase(self)}, '
                f'{nmbnan} required {text} not been set yet.')