def format_temp_unit(value: float, unit: str) -> str:
    """
    returns formatted degrees value
    Format celsius or fahrenheit degrees to nice string output.
        :param value: celsius or fahrenheit degrees value
        :param unit: 'C' for celsius or 'F' for fahrenheit degrees
        :type value: float
        :type unit: str
        :returns: value with degrees symbol
        :rtype: str
        :Example:
            >>> a = format_temp_unit(-17.78, 'c')
            >>> print(a)
            "-17.78℃"
    """
    if unit.lower() == 'c':
        return f"{value}℃"
    elif unit.lower() == 'f':
        return f"{value}℉"
    else:
        return str(value)