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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __get_arg(cls, kwds, kwd):
 """Internal helper method to parse keywords that may be property names."""

    alt_kwd = '_' + kwd
    if alt_kwd in kwds:
      return kwds.pop(alt_kwd)
    if kwd in kwds:
      obj = getattr(cls, kwd, None)
      if not isinstance(obj, Property) or isinstance(obj, ModelKey):
        return kwds.pop(kwd)
    return None