multiElementOneOf: groupShape ('|' groupShape)+

def visitMultiElementOneOf(self, ctx: ShExDocParser.MultiElementOneOfContext):
        """ multiElementOneOf: groupShape ('|' groupShape)+ """
        self.expression = OneOf(expressions=[])
        for gs in ctx.groupShape():
            parser = ShexOneOfShapeParser(self.context)
            parser.visit(gs)
            self.expression.expressions.append(parser.expression)