Converts GPRMC formats (Decimal Minutes) to Degrees Decimal.

def gprmc_to_degdec(lat, latDirn, lng, lngDirn):
    """Converts GPRMC formats (Decimal Minutes) to Degrees Decimal."""
    x = float(lat[0:2]) + float(lat[2:]) / 60
    y = float(lng[0:3]) + float(lng[3:]) / 60

    if latDirn == 'S':
        x = -x
    if lngDirn == 'W':
        y = -y

    return x, y