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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 checkIsConsistent(self):
 """ Raises a ConsistencyError if the mask has an incorrect shape. """

        if is_an_array(self.mask) and self.mask.shape != self.data.shape:
            raise ConsistencyError("Shape mismatch mask={}, data={}"
                                   .format(self.mask.shape != self.data.shape))