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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_extension_classes():
 """ Hotdoc's setuptools entry point """

    res = [SyntaxHighlightingExtension, SearchExtension, TagExtension,
           DevhelpExtension, LicenseExtension, GitUploadExtension,
           EditOnGitHubExtension]

    if sys.version_info[1] >= 5:
        res += [DBusExtension]

    try:
        from hotdoc.extensions.c.c_extension import CExtension
        res += [CExtension]
    except ImportError:
        pass

    try:
        from hotdoc.extensions.gi.gi_extension import GIExtension
        res += [GIExtension]
    except ImportError:
        pass

    return res