def format_chf(value: int, with_currencysign: bool = True, plus_sign: bool = False) -> str:
    """
    Formats a centime value into a commonly understood representation ("CHF -13.37").

    :param value: The value to format, in centimes.
    :param with_currencysign: Whether to include the currency prefix ("CHF ") in the output.
    :param plus_sign: Whether to denote positive values with an explicit "+" sign before the value.
    :return: A human-readable string representation.
    """
    sign: str = ''
    if value < 0:
        # As // and % round towards -Inf, convert into a positive value and prepend the negative sign
        sign = '-'
        value = -value
    elif plus_sign:
        sign = '+'
    # Split into full francs and fractions (centimes)
    full: int = value // 100
    frac: int = value % 100
    csign: str = 'CHF ' if with_currencysign else ''
    # Put it all together; centimes are always padded with 2 zeros
    return f'{csign}{sign}{full}.{frac:02}'


def parse_chf(value: str) -> int:
    """
    Parse a currency value into machine-readable format (integer centimes).  The prefix "CHF", the decimal point, and
    digits after the decimal point are optional.

    :param value: The value to parse.
    :return: An integer representation of the value.
    :raises: Value error: If more than two digits after the decimal point are present.
    """
    # Remove optional leading "CHF" and strip whitespace
    value = value.strip()
    if value.startswith('CHF'):
        value = value[3:]
    value = value.strip()
    if '.' not in value:
        # already is an integer; parse and turn into centimes
        return int(value, 10) * 100
    # Split at the decimal point
    full, frac = value.split('.', 1)
    if len(frac) > 2:
        raise ValueError('Needs max. 2 digits after decimal point')
    elif len(frac) < 2:
        # Right-pad fraction with zeros ("x." -> "x.00", "x.x" -> "x.x0")
        frac = frac + '0' * (2 - len(frac))
    # Parse both parts
    ifrac: int = int(frac, 10)
    ifull: int = int(full, 10)
    if ifrac < 0:
        raise ValueError('Fraction part must not be negative.')
    if full.startswith('-'):
        ifrac = -ifrac
    # Combine into centime integer
    return ifull * 100 + ifrac