ImportError: Missing optional dependency 'openpyxl'. Use pip or conda to install openpyxl.

This error message indicates that the Python package you are trying to use requires the 'openpyxl' library as an optional dependency, but it is not currently installed on your system.

To resolve this error, you can use either pip or conda to install the openpyxl library. Here are the steps to install it using pip:

1. Open a terminal or command prompt window.
2. Type the following command: `pip install openpyxl`
3. Press Enter to run the command.
4. Wait for the installation process to complete.
5. Try running your Python code again to see if the error has been resolved.

If you prefer to use conda instead of pip, you can run the following command instead:

`conda install openpyxl`

This will install the openpyxl library using the conda package manager.