code: def _validate_usepdb_cls(value):
      """Validate syntax of --pdbcls option."""
      try:
          modname, classname = value.split(":")
      except ValueError:
          raise argparse.ArgumentTypeError(
              "{!r} is not in the format 'modname:classname'".format(
                  value
              )
          )
      return (modname, classname)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import argparse
  import pdb
  import sys
  from doctest import UnexpectedException
  from _pytest import outcomes
  from _pytest.config import hookimpl
  from _pytest.config.exceptions import UsageError
label_desc: Use image node_id 3 for calling a global function with example usage: _validate_usepdb_cls(value) and returns: modname,  classname