# File lib/rbot/dbhash.rb, line 33
    def bdb_bt_compare(a, b)
      if a == nil || b == nil
        warning "CIBTree: comparing #{a.inspect} (#{self[a].inspect}) with #{b.inspect} (#{self[b].inspect})"
      end
      (a||'').downcase <=> (b||'').downcase
    end