def ev_fill(decimal_part):
    """Pad the first decimal part with zeros, taking into account E / V codes.
    """
    
    if decimal_part.startswith("V"):
        return "V" + decimal_part[1:].zfill(2)
    elif decimal_part.startswith("E"):
        return "E" + decimal_part[1:].zfill(3)
    else:
        return decimal_part.zfill(3)