def validate_read_preference(dummy, value):
    if not isinstance(value, _ServerMode):
        raise TypeError("%r is not a read preference." % (value,))
    return value
Converts from a comma-separated, base64-hex-encoded
dataset/ETHPy150Open mongodb/mongo-python-driver/pymongo/common.py/validate_read_preference--crossover with--dataset/ETHPy150Open viewfinderco/viewfinder/backend/db/schema.py/UnpackPlacemark