def _fix_up ( self , cls , code_name ) : self . _code_name = code_name if self . _name is None : self . _name = code_name
python only make property setter
Internal helper called to tell the property its name .
def _fix_up(self, cls, code_name):
    """Internal helper called to tell the property its name.

    This is called by _fix_up_properties() which is called by
    MetaModel when finishing the construction of a Model subclass.
    The name passed in is the name of the class attribute to which the
    Property is assigned (a.k.a. the code name).  Note that this means
    that each Property instance must be assigned to (at most) one
    class attribute.  E.g. to declare three strings, you must call
    StringProperty() three times, you cannot write

      foo = bar = baz = StringProperty()
    """
    self._code_name = code_name
    if self._name is None:
      self._name = code_name