changing { and } in str.format()

[Skaperen]

i have a bunch of generated strings (read from a file) that are being processed in my script by str.format() with a bunch of args. today, i ran into a case where i have a '{' in one of the strings and str.format() is upset by it. the normal solution with str.format is '{'->'{{'. but this is turning out to be impossible to do because all the '{' are being doubled. what i can do, easily, is have the various '{}' and '{foo}' that are being added changed to something else like maybe '[]' and '[foo]' (i will need to grep this data a few times to see what i can safely pick).

is there a way to have str.format() use an alternate for '{}' and '{foo}'?