code: function forEachChildExpression(expr, modelClass, callback) {
    if (expr.node.$allRecursive || expr.maxRecursionDepth > RELATION_RECURSION_LIMIT) {
      throw modelClass.createValidationError({
        type: ValidationErrorType.RelationExpression,
        message: `recursion depth of eager expression ${expr.toString()} too big for JoinEagerAlgorithm`
      });
    }
  
    expr.forEachChildExpression(modelClass, callback);
  }
docs: Given a relation expression, goes through all first level children.