# File lib/rbot/core/utils/filters.rb, line 124
    def filter_names(group=nil)
      if group
        gkey = group.to_sym
        return [] unless defined? @filter_group and @filter_group.key?(gkey)
        return @filter_group[gkey].keys
      else
        return [] unless defined? @filters
        return @filters.keys
      end
    end