Setting values to None results in an error

Using the setter in a UIMAType object with None gives an error. Somewhat fixable like this:

    @simple_coref.setter
    def simple_coref(self, ent: SimpleCorefEntity):
        if ent is not None:
            self.anno["SimpleCoref"] = ent.anno

A better way would probably be to write a generic setter function taking care of this, like

def _set_attr(self, uima_attribute_name, value):
    ...

and use this everywhere.