In both cases, the variable is set to the name of the function, and you must have defined the function in your shell configuration before kube_ps1 is called. The function must accept a single parameter and echo out the final value.
### Bug Reports and shell configuration
Due to the vast ways of customizing the shell, please try the prompt with a
minimal configuration before submitting a bug report.
This can be done as follows for each shell before loading kube-ps1: