def empty_if_none(fn):

  def wrapper(value):

    if value is None:
      return ''
    return fn(value)

  return wrapper


# Key helpers.
A wrapper for a value to return '' if it's None. Useful on export.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/bulkload/transform.py/empty_if_none