---
title: Using Nested Functions in Data Blocks
description: "*Failure to correctly nest functions may result in Data Blocks not functioning properly and/or Data Blocks not being exported/imported as expected via the Assette [VS Code PLugin](https://learn.assette.com/docs/visual-studio-code-python-setup/).* When creating a Data Block, developers may sometimes want to create nested functions…"
url: "https://learn.assette.com/docs/using-nested-functions-in-data-blocks/"
updated: "2024-11-08"
category: Developers / Developer Tools / Data Block Editor
---

# Using Nested Functions in Data Blocks

*Failure to correctly nest functions may result in Data Blocks not functioning properly and/or Data Blocks not being exported/imported as expected via the Assette [VS Code PLugin](https://learn.assette.com/docs/visual-studio-code-python-setup/).*

When creating a Data Block, developers may sometimes want to create nested functions (also sometimes called "Inner Functions" or "Sub-functions") to help organize their code. Assette Data Blocks do allow developers to use nested functions, however, it is important to note that any functions declared within another function (i.e., a nested function) must either be defined globally or called separately within a Data Block. Shown below, sub_function1 is not included in the scope sub_function2(), and therefore is sub_function1() is defined globally at the beginning of the script.

```
#----Code start identification-do not remove this line---

    global sub_function1
    def sub_function1(func_params1):
        # Sub-function 1 goes here
        return func_params1*2

    def sub_function2(func_params2):
        # Sub-function 1 goes here
        return sub_function1(func_params2)*func_params2

    final_result = dict()
    # Call the sub-functions and do activities to populate the final_result
    final_result["answer"] = sub_function2(params["num1"])
    response["data"] = final_result

#----Code end identification-do not remove this line---
```

If one were to preview the results via the [Data Block Editor](https://learn.assette.com/docs/data-objects-editor-overview/), they would see that the value of "answer" is 18. However, attempting to run the above code snippet of code directly in VS Code produces a NameError, as response has not been defined.

![Using Nested Functions in Data Blocks 1](https://learn.assette.com/wp-content/uploads/2024/11/image-13-1024x524.png)

To run in an IDE, simply wrap the Data Block's code, leaving "global" in place, as shown below.

```
def execute(response, read, params):
    # Main activity goes here

#----Code start identification-do not remove this line---

    global sub_function1
    def sub_function1(func_params1):
        # Sub-function 1 goes here
        return func_params1*2

    def sub_function2(func_params2):
        # Sub-function 1 goes here
        return sub_function1(func_params2)*func_params2

    final_result = dict()
    # Call the sub-functions and do activities to populate the final_result
    final_result["answer"] = sub_function2(params["num1"])
    response["data"] = final_result

#----Code end identification-do not remove this line---

if __name__ == "__main__":
    response = {}
    execute(response, None, {"num1":3})
    print(response)
```

Then when importing via Assette's [VS Code Plugin](https://learn.assette.com/docs/installing-the-assette-vs-code-plug-in/), only the inner block, including the global definition, is imported to Assette and the Data Block can be run 'as is'.

![Using Nested Functions in Data Blocks 2](https://learn.assette.com/wp-content/uploads/2024/11/image-14-1024x567.png)