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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 isModified(self):
 """Check if either the datastream content or profile fields have changed and should be saved to Fedora. :rtype: boolean """

        # NOTE: only check content digest if locally cached content is set
        # (content already pulled or new content set); otherwise this
        # results in pulling content down to checksum it !
        return self.info_modified or \
            self._content and self._content_digest() != self.digest