def METHOD_NAME(self, node):
    concept = node.eclfocusconcept()
    if concept:
        constraint_operator_node = node.constraintoperator()
        if constraint_operator_node:
            operator = self.visit(constraint_operator_node)
        else:
            operator = None
        value = self.visit(concept)
        return {
            "type": "expr",
            "operator": operator,
            "value": value,
        }
    else:
        return self.visit(node.expressionconstraint())