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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 render_markdown(text, context=None):
 """ Turn markdown into HTML. """

    if context is None or not isinstance(context, dict):
        context = {}
    markdown_html = _transform_markdown_into_html(text)
    sanitised_markdown_html = _sanitise_markdown_html(markdown_html)
    return mark_safe(sanitised_markdown_html)