Yaml formatting with date-time values

This came up in some peak-load management PRs (and was noted by @vijay092). In these PRs, there are two required control parameters that are supposed to be in date-time format as HH:MM:SS

peak_range:
   start: 12:00:00
   end: 20:00:00

When these are loaded with load_yaml(), the values are converted to seconds from midnight. Aka

config = load_yaml(filepath)
config["peak_range"]["start"] # this value is an integer of 43200
config["peak_range"]["end"] # this value is an integer of 72000

I think that two options to handle this are:

• allow string formatting in the pre-commit for yaml files when values have :. This means that the yaml files would be able to look like:

peak_range:
   start: "12:00:00"
   end: "20:00:00"

OR

• add something into load_yaml() that prevents this conversion. So that the yaml file values formatted as HH:MM:SS are loaded as strings. This stack overflow post may have some options for this

@jaredthomas68 - how did you handle this in your peak-load PR?

Locate load_yaml() and trace the loader used for the peak_range example; inspect the referenced peak-load PRs for the intended handling. Add focused coverage showing that HH:MM:SS values are preserved as strings, then verify both start and end behavior against the issue's examples.