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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 update_repodata(self, channels=None):
 """Update repodata from channels or use condarc channels if None."""

        norm_channels = self.conda_get_condarc_channels(channels=channels,
                                                        normalize=True)
        repodata_urls = self._set_repo_urls_from_channels(norm_channels)
        self._check_repos(repodata_urls)