docs: def types(self, *args):
          """Used for debugging, returns type of each arg.
              TYPES,ARG_1,...,ARG_N
  
          %{TYPES:A,...,10} -> 'str(A) str(B) ... int(10)'
          """
          return ', '.join(['{0}({1})'.format(type(arg).__name__, arg) for arg in args])