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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 current_version_option_validator(ctx, param, value):
 """If a version string is provided, validates it. Otherwise it tries to determine the current version from the last Git tag that matches ``tag_pattern`` option. Return a :class:`~braulio.version.Version` object or **None**. """


    current_version = None

    if value:
        try:
            current_version = Version(value)
        except ValueError:
            ctx.fail(f"{value} is not a valid version string")

    # Look for the last git tag for the curren version
    git = Git()
    tag_pattern = ctx.params["tag_pattern"]
    versions = tag_analyzer(git.tags, tag_pattern, Version)

    # User provided current version. Try to find a tag that match it.
    if current_version:
        for version in versions:
            if version == current_version:
                current_version = version
                break
    elif versions:
        current_version = versions[0]

    ctx.params["current_tag"] = current_version.tag if current_version else None
    ctx.params["versions"] = versions

    return current_version