diff_orig <- soda %>%
  group_by(location) %>%
  summarize(prop_cola = mean(drink == "cola")) %>%
  summarize(diff(prop_cola)) %>%
  pull()

 soda_perm <- soda %>%
  specify(drink ~ location, success = "cola") %>%
  hypothesize(null = "independence") %>%
  generate(reps = 100, type = "permute") %>%
  calculate(stat = "diff in props", 
              order = c("west", "east"))

soda_perm %>% 
    summarize(proportion = mean(diff_orig >= stat))