def units_abbreviation():
    """Get text for the current Rhino doc units abbreviation (eg. 'm', 'ft')"""
    try:
        import scriptcontext
        units = str(scriptcontext.doc.ModelUnitSystem).split('.')[-1]
    except ImportError:
        units = 'Meters'
    if units == 'Meters':
        return 'm'
    elif units == 'Millimeters':
        return 'mm'
    elif units == 'Feet':
        return 'ft'
    elif units == 'Inches':
        return 'in'
    elif units == 'Centimeters':
        return 'cm'
    else:
        raise ValueError("You're kidding me! What units are you using?" +
            units +
            """?
Please use Meters, Millimeters, Centimeters, Feet or Inches."""
            )
