             project_id : required
             groups     : PROJECT_GROUPS
             cb         : required    # cb(err, {group:[{account_id:?,first_name:?,last_name:?}], ...})
-        if not @_validate_uuids(opts) then return
+        if not @_validate_opts(opts) then return
         groups = undefined
         names  = undefined
         async.series([
-            # get account_id's of all users
-            (cb) =>
+            (cb) =>
+                # get account_id's of all users of the project
                 @get_project_data
                     project_id : opts.project_id
                     columns    : opts.groups

        opts = defaults opts,
            account_id : required
            cb         : required
        if not @_validate_uuids(opts) then return
        @table('accounts').get(opts.account_id).delete().run(opts.cb)

    account_exists: (opts) =>

            use_cache    : true
            cache_time_s : 60*60        # one hour
            cb           : required     # cb(err, map from project_id to string (project title))
        if not @_validate_opts(opts) then return

    # cb(err, array of account_id's of accounts in non-invited-only groups)
    get_account_ids_using_project: (opts) ->
        opts = defaults opts,
            project_id : required
            cb         : required
        if not @_validate_opts(opts) then return

    ###
    # STATS
