def normalize(value, unit):
    """Converts the value so that it belongs to some expected range.

    Returns the new value and new unit.

    E.g:

    >>> normalize(1024, 'KB')
    (1, 'MB')
    >>> normalize(90, 'min')
    (1.5, 'hr')
    >>> normalize(1.0, 'object')
    (1, 'object')
    """
    if value < 0:
        raise ValueError('Negative value: %s %s.' % (value, unit))

    if unit in functions.get_keys(INFORMATION_UNITS):
        return _normalize_information(value, unit)
    elif unit in TIME_UNITS:
        return _normalize_time(value, unit)
    else:
        # Unknown unit, just return it
        return functions.format_value(value), unit