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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 get_release_data(self):
 """Get release data for this release. Returns: dict. """

        previous_package = self.get_previous_release()
        if previous_package:
            previous_version = previous_package.version
            previous_revision = previous_package.revision
        else:
            previous_version = None
            previous_revision = None

        if self.vcs is None:
            return dict(vcs="None",
                        previous_version=previous_version)

        revision = None
        with self.repo_operation():
            revision = self.vcs.get_current_revision()

        changelog = self.get_changelog()

        # truncate changelog - very large changelogs can cause package load
        # times to be very high, we don't want that
        maxlen = config.max_package_changelog_chars
        if maxlen and changelog and len(changelog) > maxlen + 3:
            changelog = changelog[:maxlen] + "..."

        return dict(vcs=self.vcs.name(),
                    revision=revision,
                    changelog=changelog,
                    previous_version=previous_version,
                    previous_revision=previous_revision)