def _debug_spacing(col_starts, row_starts):  # pragma: no cover
    """Return a string suitable for inserting inside an <svg> tag that
    draws green lines where columns and rows start. This is very useful
    if you're developing this code and are debugging spacing issues.
    """
    t = ''
    for i, cs in enumerate(col_starts):
        t += (
            f'<line id="cs-{i}" '
            f'x1="{cs}" x2="{cs}" y1="0" y2="{row_starts[-1]}" '
            f'stroke="green" stroke-width="1" />'
        )
    for i, rs in enumerate(row_starts):
        t += (
            f'<line id="rs-{i}" '
            f'x1="0" x2="{col_starts[-1]}" y1="{rs}" y2="{rs}" '
            f'stroke="green" stroke-width="1" />'
        )
    return t
Return a string suitable for inserting inside an <svg> tag that
    draws green lines where columns and rows start. This is very useful
    if you're developing this code and are debugging spacing issues.
    
cirq-core/cirq/contrib/svg/svg.py