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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 ensure_v8_src():
 """ Ensure that v8 src are presents and up-to-date """

    path = local_path('v8')

    if not os.path.isdir(path):
        fetch_v8(path)
    else:
        update_v8(path)

    checkout_v8_version(local_path("v8/v8"), V8_VERSION)
    dependencies_sync(path)