Executing an R notebook via papermill in a separate Python notebook

Question

I have a notebook using a custom_python kernel that calls papermill to execute an another notebook which uses a conda_r_custom_r kernel. When I run the following

import papermill as pm

pm.execute_notebook(
    'my-r-notebook.ipynb',
    output_path=None,
    parameters=dict(param=4),
    kernel_name='conda_r_custom_r',
    language='R'
)

I get an error NoSuchKernel: No such kernel named conda_r_custom_r. I'm running this on an AWS SageMaker instance where I've created a bunch of custom environments.