def coerce_bool(value):
    """Coerce a value to be a boolean"""
    if isinstance(value, str):
        return value[0].lower() in ['t', 'y', '1']
    else:
        return bool(value)


def convert_units(value, old_unit, new_unit):
    """Convert a value from one unit to another"""
    if old_unit == 'in' and new_unit == 'mm':
        return value * 25.4
    if old_unit == 'mm' and new_unit == 'in':
        return value / 25.4
    if old_unit == 'in' and new_unit == 'pt':
        return value * 72.0
    if old_unit == 'pt' and new_unit == 'in':
        return value / 72.0
    if old_unit == 'mm' and new_unit == 'pt':
        # Convert to in and then to pt
        return (value / 25.4) * 72.0
    if old_unit == 'pt' and new_unit == 'mm':
        # Convert to in and then to mm
        return (value / 72.0) * 25.4
    return value