local function find_digest_in_sorted_set(name, digest)

local cursor  = 0
local count   = 5
local pattern = "*" .. digest .. "*"
local found   = false

log_debug("searching in:", name,
          "for digest:", digest,
          "cursor:", cursor)
repeat
  local pagination  = redis.call("ZSCAN", name, cursor, "MATCH", pattern, "COUNT", count)
  local next_cursor = pagination[1]
  local items       = pagination[2]

  if #items > 0 then
    log_debug("Found digest", digest, "in zset:", name)
    found = true
  end

  cursor = next_cursor
until found == true or cursor == "0"

return found

end