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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 dg_value(self, descriptor_group):
 """ Return the canonical value of a descriptor of the character, provided it is present in the given descriptor group. If not present, return ``None``. :param IPADescriptorGroup descriptor_group: the descriptor group to be checked against :rtype: str """

        for p in self.descriptors:
            if p in descriptor_group:
                return descriptor_group.canonical_value(p)
        return None