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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 resolve_revision(self, dest, url, rev_options):
 """ Resolve a revision to a new RevOptions object with the SHA1 of the branch, tag, or ref if found. Args: rev_options: a RevOptions object. """

        rev = rev_options.arg_rev
        sha, is_branch = self.get_revision_sha(dest, rev)

        if sha is not None:
            rev_options = rev_options.make_new(sha)
            rev_options.branch_name = rev if is_branch else None

            return rev_options

        # Do not show a warning for the common case of something that has
        # the form of a Git commit hash.
        if not looks_like_hash(rev):
            logger.warning(
                "Did not find branch or tag '%s', assuming revision or ref.",
                rev,
            )

        if not rev.startswith('refs/'):
            return rev_options

        # If it looks like a ref, we have to fetch it explicitly.
        self.run_command(
            ['fetch', '-q', url] + rev_options.to_args(),
            cwd=dest,
        )
        # Change the revision to the SHA of the ref we fetched
        sha = self.get_revision(dest, rev='FETCH_HEAD')
        rev_options = rev_options.make_new(sha)

        return rev_options