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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 region_by_identifier(self, identifier):
 """Return region of interest corresponding to the supplied identifier. :param identifier: integer corresponding to the segment of interest :returns: `jicbioimage.core.region.Region` """


        if identifier < 0:
            raise(ValueError("Identifier must be a positive integer."))

        if not np.equal(np.mod(identifier, 1), 0):
            raise(ValueError("Identifier must be a positive integer."))

        if identifier == 0:
            raise(ValueError("0 represents the background."))

        return Region.select_from_array(self, identifier)