PyPRT can be used in ArcGIS Notebooks. To do so, the following steps are required.

ArcGIS Notebooks in ArcGIS Pro
https://www.esri.com/en-us/arcgis/products/arcgis-notebooks/workspace-options/arcgis-pro

1. Clone the default conda environment directly in Pro or create a new one.
2. Install PyPRT (conda install -c esri pyprt) inside the new environment (using the Python command prompt for example).
3. Restart Pro and open a new Notebook.
4. Import PyPRT (import pyprt) to use PyPRT.

ArcGIS Notebooks on ArcGIS Online
https://www.esri.com/en-us/arcgis/products/arcgis-notebooks/workspace-options/arcgis-online

1. Install PyPRT (!conda install -c esri pyprt --yes) in the notebook cell.
2. Import PyPRT (import pyprt).
3. Import the ArcGIS API for Python (from arcgis.gis import GIS) and initialize a GIS object (gis = GIS("home")).
4. Initialize PyPRT (pyprt.initialize_prt()).
5. Use PyPRT and the Python API functionalities.