def _select_report_color(spec_coverage_percent: int):
    """
    >>> _select_report_color(0)
    'red'
    >>> _select_report_color(50)
    'red'
    >>> _select_report_color(84)
    'red'
    >>> _select_report_color(85)
    'yellow'
    >>> _select_report_color(90)
    'yellow'
    >>> _select_report_color(99)
    'yellow'
    >>> _select_report_color(100)
    'green'
    >>> _select_report_color(101) # doctest: +IGNORE_EXCEPTION_DETAIL
    Traceback (most recent call last):
    ValueError: Invalid value: coverage_percent=101
    >>> _select_report_color(-1) # doctest: +IGNORE_EXCEPTION_DETAIL
    Traceback (most recent call last):
    ValueError: Invalid value: coverage_percent=-1
    """
    percents_colors = {
        84: "red",
        99: "yellow",
        100: "green",
    }
    if spec_coverage_percent >= 0:
        for percent, color in percents_colors.items():
            if spec_coverage_percent <= percent:
                return color
    raise ValueError(f"Invalid value: {spec_coverage_percent=}")