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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 _convert_reftype_to_jaeger_reftype(ref):
 """Convert opencensus reference types to jaeger reference types."""

    if ref == link_module.Type.CHILD_LINKED_SPAN:
        return jaeger.SpanRefType.CHILD_OF
    if ref == link_module.Type.PARENT_LINKED_SPAN:
        return jaeger.SpanRefType.FOLLOWS_FROM
    return None