No way to get many values (only getting all values)

[gabriels1234]

Describe the problem

For a Constance setup that has many many values, and to optimize for speed, get_values() is more expensive than it could be.

def get_values():  # <-- No arguments, gets all the values
    """
    Get dictionary of values from the backend
    :return:
    """

    # First load a mapping between config name and default value
    default_initial = ((name, options[0])
                       for name, options in settings.CONFIG.items())
    # Then update the mapping with actually values from the backend
    initial = dict(default_initial, **dict(config._backend.mget(settings.CONFIG)))

    return initial

I was wondering if there's interest in modifying this function to allow for optionally specifying which values to get. I could make a PR for it. (cc/ @syre )
Thanks!

[Mogost]

PR is always welcome!

Isn't this a duplicate of #344 ?

[camilonova]

It will add extra complexity for an uncommon use case. Even if we get a PR, it isn't the right fit.