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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 git_tag(repo_dir, tagname, message=None, force=True):
 """Create an annotated tag at the current head."""

    message = message or "%s" % tagname
    command = ['git', 'tag', '--annotate', '--message', message]
    if force:
        command.append('--force')
    # append the tag as the final arg
    command.append(tagname)
    return execute_git_command(command, repo_dir=repo_dir)