def canonicalize_name(name)
      if name == nil or name == SEP
        return name
      elsif name[0] == SEP[0]
        return name.split(/\/+/).join(SEP)
      else
        return SEP + name.split(/\/+/).join(SEP)
      end
    end
def canonicalize_name(name)
      if name == nil or name == SEP
        return name
      elsif name[0] == SEP[0]
        return name.split(/\/+/).join(SEP)
      else
        return SEP + name.split(/\/+/).join(SEP)
      end
    end
start with '/' and use single '/' for names

 @param [String] name input name
 @return [String] canonicalized name