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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 _format_summary(lines, element, spacer=" "):
 """Adds the element's summary tag to the lines if it exists."""

    summary = spacer + element.summary
    if element.summary == "":
        summary = spacer + "No description given in XML documentation for this element."
    lines.append(summary)