ModuleNotFoundError: No module named 'mnist_loader'

This error message indicates that the Python script is trying to import a module named 'mnist_loader', but such module cannot be found in the system.

To resolve this error, you can try the following steps:

1. Check if the 'mnist_loader' module is included in your project files. If not, you can download it from a reliable source and add it to your project.

2. Make sure that the 'mnist_loader' module is installed in your Python environment. You can install it using the pip command:

`pip install mnist_loader`

3. Check if the module name is spelled correctly in the import statement.

For example, if the import statement is:

`import mnist_loader`

Then the filename of the module should be 'mnist_loader.py'.

If the filename is different, you need to update the import statement accordingly.