code: def format(
      tokens, formatter, outfile=None
  ):  # pylint: disable=redefined-builtin
      """
      Format a tokenlist ``tokens`` with the formatter ``formatter``.
  
      If ``outfile`` is given and a valid file object (an object
      with a ``write`` method), the result will be written to it, otherwise
      it is returned as a string.
      """
      try:
          if not outfile:
              realoutfile = (
                  getattr(formatter, "encoding", None)
                  and BytesIO()
                  or StringIO()
              )
              formatter.format(tokens, realoutfile)
              return realoutfile.getvalue()
          else:
              formatter.format(tokens, outfile)
      except TypeError as err:
          if isinstance(err.args[0], str) and (
              "unbound method format" in err.args[0]
              or "missing 1 required positional argument" in err.args[0]
          ):
              raise TypeError(
                  "format() argument must be a formatter instance, "
                  "not a class"
              )
          raise
  
imports: import sys
  from pygments.util import StringIO, BytesIO
label_desc: Use image node_id 2 for calling a global function with example usage: format(tokens, formatter, outfile) and returns: realoutfile