option_1=ChoiceOption(name="var1",doc="the first variable",values=("a","b","c"),properties=frozenset({"basic","mandatory"}),informations={'type':'choice'})
option_2=ChoiceOption(name="var2",doc="the second variable",values=("a","b","c"),properties=frozenset({"basic","mandatory"}),informations={'type':'choice'})
option_3=ChoiceOption(name="var3",doc="the third variable",values=("a","b","c",None),properties=frozenset({"standard"}),informations={'type':'choice'})